It is very very very difficult to determine if it a misdiagnosis or not. I have been diagnosed with bi-polar and ADHD; however, I often second guess it. As for wanting to be a fireman then a nurse, I just switched my major from welding to graphic design. I get the same depressed stressed anxious f'ing crazy perspective changes all day everyday. The thing is that ADHD and Bi Polar Go hand in hand and a lot of people with ADHD or ADD have Bi-Polar and vice versa. But stimulants that are used to treat ADD and ADHD can cause one to have the same symptoms of Bi Polar and the benzodiazapines like klonopin xanax etc and mood stabilizers will just make you worse if your not bi polar and its just medication or the ADD. My suggestion would be to try an anti depressant because if you are add or adhd it can significantly help and if you are bi polar and take an anti depressant you will most likely feel much more anxious and will not feel good so then you will be able to determine if it was a correct diagnosis. Hope this helps, hang in there