Do you ever think self diagnosis is called for?
I think this is a borderline question. As a rule of thumb, we do not answer questions about individual health problems in favor of asking the author to see a professional, for both ethical and practical reasons. And let me be absolutely unequivocal here: you should see a professional. But this is fundamentally a general question about self-diagnosis, so I'm going to answer that.

It's always good to educate yourself. Accurate self diagnosis is necessarily impossible, however―what you can see depends on what you know, and what you know depends on what you have seen, etc. This is uncontroversial. Being educated is therefore very helpful when seeing a professional, which I again strongly encourage you to do, but it is never a substitute for seeing a professional when you have problems.