Can I go to my gp to get allergy testing done or does it have to be an allergist?

Depends. Some family practitioners who are trained and are conscientious do perform appropriate allergy testing, but some (and, unfortunately, some Allergists too) depend on blood tests that are too easily misinterpreted or even inappropriate. Trust the doctor that starts with a detailed history/conversation followed by targeted testing (skin testing is most accurate for most problems) and explains clearly.