I've only had one sexual partner. He performed oral sex on me multiple times. I never knew oral sex could transmit STDs so I never thought to get tested. This incident was almost 2 years ago. I recently called him up and he said he was clean - but I am not sure if I believe him, although he has no reason to lie to me - we are no longer together - he said he always had protected sex and the girls he was with before me were all clean.
Recently I've noticed I have diarrhea (but I also just got back from over seas a month ago so it might be from that) and abdominal pain on my left side and sharp pains that seem to be coming from my anus - I also am known to have really poor eating habits so my family thinks it's gastric or a urinary infection. Other than that, I get the common cold now and then, my vagina only itches when I shave, and then but I haven't experienced any other symptoms.
Is it common to get STDs from receiving oral sex? Should I get tested? I know sites say that you can get STDs from oral and that its lower risk than vaginal and anal. But how common is it and what are the chances of a female receiving oral getting HIV/STDs?