It depends on whether or not you want to be a doctor.
If you think the medical school application process is tough, think about medical school and residency -- they will be much worse. If you're not sure that you want to be a doctor, that should answer your question.
I agree with edmadison. The profession is based upon sacrifice, whether it be to the patient or the medical establishment. A deep desire must be there to fuel you through all of the heavy brush. You reaaly have to ask yourself whether you REALLY want it or not because the struggle will always be there.
I think it's worth it. Whenever, I get frustrated with the thought of this long arduous process, I got and put on my running shoes and run till it's out of my system. So, the accompanying stress does have its health benefits.
On a more serious note, I think G3 is right on the ball. This takes a lot of dedication; do you have the stamina to go through with it all the way until you reach the completion point (residency/fellowship)?