Service Dogs are not certified. If someone tells you they can certify your dog, run the other way. Training of a serivce dog from puppyhood takes about 2 years. the dog must have basic obedience commands very solid, must not have agression issues (barking, nipping at others, lunging on the leash etc), must be able to pass a public access test, must be able to ignore distractions when working, there are other things that you should also have the dog be able to handle, but these things are a start. THe dog also needs to be able to do a task that mitigates your disability.
I agree with Roxie, if you haven't become stable on medication or through other coping methods, you may send your dog confusing signals. At home that won't matter so much but in public it could be a disater waiting to happen. I do not know you or your medical issues and I am not a doctor, so I can't tell you if it would be good for you or not. You need to take this up with your therapists and doctors to help you make this decision.
I would also suggest that you need to decide if you will be training your dog yourself, with the assistance of a trainer, or looking to a program to provide the dog. I would also suggest reading a lot about Service Dogs and their training so that you understand the demands that this will put on both you and your dog.