They didn't test me either - they didn't have to because I was in a full blown manic state.
Unfortunately, alot of us manage to not be diagnosed until quite late.
The depressions are obvious, and if we get a little tooooo happy then everyone is just too plain relieved that we are getting out of bed and doing things to see that it is way too much the opposite direction.
I know that there are some manias that are triggered the first time by anti-depressants - that sounds like what happened to you.
If you are younger it is actually a GOOD thing believe it or not!
I was 30 before they ever figured it out for me and I can tell you that my life between 13 & 30 was pretty rocky...
Glad you found us!