So read up on the different medications,but your doctor will know which one to start with, given whether you're stressed or lethargic,etc. If you have poor or no insurance, you can tell him/her you want one available in generic form.
You'll have to take all your medical issues into account, whether you are trying to lose weight, etc. Be sure to give your doctor as much information as possible. After that, bear in mind that they can take weeks to become active and may not work for you - but then you try another.
Just give it a shot, though you might try regular exercise first, ifyou haven't already.