Dddduuuuuuddddeeeee, I so get it. You're a dental student and what you're feeling is well within the bell curve of what the average dental student experiences. You're in a pressure cooker; driving through a long dark tunnel; drinking from a fire hose. There's a reason dental school has many analogies. What you must remember is that it's all artificial and none of it is the real world. You can use the information they give you in the real world, but the way it's presented and the way you have to live while receiving it is pure, utter, 100%, grade A, BS. Big hot steamy BS. So no wonder you're depressed when the world you're currently living in isn't based on reality. That's kinda what makes you normal, isn't it? But it ends. One day it's over, and you're out, and your narcissistic prosth instructor isn't getting his rocks off making you miserable, and you don't have to remember biochemical pathways at gunpoint, and you aren't drawing excursive pathways on the headboard in your sleep. And F*** waxing. Because nobody does that in real life.
Clinic is better. Clinic will start to make you happy in secret little ways that only your starved ego and deprived self worth can understand. Sure, it has its own stressors, but you can see the reality seeping back into your life. Don't wig out about requirements even though it's super-duper tempting. You will get them, they will show up on your schedule, they materialize. Don't sit there and drop beads of sweat into the patient's mouth because it's your first IAN block. You actually do know your landmarks, you won't forget to aspirate, and if you get that puddle of lidocaine somewhere on the correct side of their body they'll start to feel something. And they're not gonna feel the second one if you need it. You will achieve successes in clinic, and they will be like salve to your psyche, and nobody will be able to take them away from you, and you will know that they are true, and the depression will start falling off of you like chunks of dried mud. I've been there. A lot of us have. Have faith.
In the mean time do stuff in the sunshine while you can. Vit. D is a hell of a drug. Get a stupid secret little hobby that nobody knows about and is something you can look forward to when you get home. I cared about landscaping and yardwork during 3rd and 4th year, and having the shiniest tires in the world on my truck. I mean my tires looked like polished obsidian. Pristine. Never in my life have I ever given a damn about tires, but it kept me sane during school. Also killing wasps. Find you a wasp nest and a can of WD-40 and have it the f*** out with those little bastards. You'll come out feeling alive. You might even paint your exploits on the wall like cavemen did after slaying a wooly mammoth.
Hang in there. You do deserve to be there, you are smart, you are capable, and you will be a good dentist. Looking forward to seeing you at some CE courses in a few years.