I think it's also not unheard of for people to convince themselves they have a condition that they don't really have. Especially with mental health problems where symptoms aren't as easy to measure as, say, fever/no fever, vomiting/not vomiting or whatever. Someone can read the DSM description of bipolar or something and think, "hey, I have some of those symptoms, that explains everything" when some symptoms might occur in lots of different conditions. I doubt your T meant to scold you or act like your issues aren't important, but it's worth telling him how it made you feel. Your sense that your problems don't matter to him is important to bring up.