GPs are much more knowledgeable about mental disorders these days but while medication can be helpful, it is always best to see a psychologist and learn cognitive behavioral therapy. I have had problems for years and so this last go around, I did go to my GP and get put on medication but I had already had therapy years ago and already knew controlled breathing, self-coaching, etc. You on the other hand do not and it really is an invaluable tool in the battle against OCD and anxiety.
I saw my family doctor. It's a pain to go to the bathroom without these thoughts. All she told me was that it was very common and prescribed me medication I was waiting for her to talk about a therapist or something but she never did. Maybe i should of asked but i trusted her to give me the help i needed.
In answer to your first question...no you are not going to get pregnant this way. In answer to your second question, I personally think that cognitive behavioral therapy should be taught in conjunction with medication if you are taking meds. Meds help a lot but it is not a cure all. You still need to know how to help yourself when you have breakthrough anxiety from thoughts. What doctor did you see? A GP?