I can comment on this in a manner that no one else on this site can. I was in your shoes 14 years ago with the exception of being on academic probation. I was in my 2nd year of dental school. My heart was not in d-school at all. I was wanting to be out playing rather than sitting through lectures. I was passing my classes, but as long as I was passing I didn't care how I did. I partied at night and slept through lectures during the day. Luckily, we had all the lecture materials given to us at the beginnning of the semester, so I could cram for the exams and learn enough to get by the night before an exam. I was placing myself in a very bad place where if I had stayed in school, I really don't think I would have passed my boards part 1. Later in the fall of my 2nd yr, I ended up withrawing from d-school. For ME, it really was the best decision of my life. I would not have done my patients any good had I stayed in school the first time. My heart wasn't there. Being a dentist at that point in my life wasn't important to me. It was a very hard decision to make especially knowing I had a huge amount of student loans to pay back without a job to pay it back with. I ended up having to live off my credit card for quite some time and racked up a lot of debt until I moved back in with my parents. I found two full time jobs at $8/hr to pay back my loans and credit card bill. I did this for a year until I joined the Navy.
If I had not withdrawn when I did, I really don't know where my life would be right now. But, I am sure I would not be as happy with my life and my career as I am now. I matured a lot. With the coaxing of some friends who were dentists, I decided to give dentistry a shot again. I volunteered for a year and developed a love for it. I re-applied to d-school and was accepted to every school I applied to. Not one school I applied to held my decision to withdraw from school the first time against me. This time in d-school has been a long journey. There have been many reasons for me where I could have given up. This time in d-school, I have dealt with the murder of my classmate and good friend who I sat with in class every day. I've dealt with my own medical issues where it looked like I had a severe case of Parkinson's disease (and still have to deal with it on occassions). I've dealt with my having mother-in-law pass away in her house and wasn't found for 15 days - so I had to deal with the cleanup and everything with her house. I have had to deal with my house receiveing around $85,000 in damage due to hurricane Ike and not being able to live in it for 14 months. I have had to deal with the birth of my twins where one of the babies had a severe cardiac arrythmia which led to having to take her to the ER at 1 1/2 weeks of age while administering rescue breaths at 2 in the morning because she was in agonal respirations. Three weeks after their birth, my wife developed a cardiac condition. Then I had to basically suck it up and bite the bullet raising my children while my wife worked and went to school full time as well. Then I had to deal with finding out my grandfather had terminal cancer and was sent home one day saying they cannot do anything more for him and that he enjoy the rest of his time with his family (still ongoing). Then, the first day of school this year, my wife has a miscarriage. And, to top things off, my wife has an appointment with an oncologist this coming Wed because of lesion that was found on an MRI that was taken because she was having severe knee pain. My point to all this is that this time in d-school, I have dealt with a lot of crap. But, because I have been in the right mindset and really want d-school this time, nothing is keeping me away even though it will have taken me 6 years to finish d-school this time. Had I gone through these things the first time in d-school, I would have laughed and just said "eff you school, I am out of here."
For the OP, I know this is a very hard decision for you. Been there. Really look things over before you withdraw from school. Talk to a counselor. Talk to a few professors you trust. Do not take this decision lightly. Do I think your chances of getting into d-school will be over if you quit d-school? Not necessarily, but then again you are on probation right now. If you really want to be a dentist right now, then tough it out. Life sucks at times. School stinks at times. Believe me, there is an end to this all. If you love dentistry, sticking with it will be worth it in the end. But, if you really don't care for dentistry, then maybe dentistry is not for you at this stage in your life. If this is the case, do some serious soul searching before you withdraw. Talk to the admin at the school. Find out what your options are. NO ONE here on SDN can tell you what your options are. If you do withdraw, you will need to make sure you can sell yourself if you re-apply to d-school or any other professional school. They will want evidence you are ready for the committment it will take to make it through their program.
No matter what you choose, I don't envy you right now. I know this is a very hard decision for you. Think it through hard because you want to make sure you do not regret your decision in the end. I thought my decision through fo months before I made my decision. Fortuneately, for me, I know I made the right decision. I hope, in the end, you do too. Good luck. If you want to run things past me, feel free to PM me!