Are my symptoms STD-related?

A month ago I was ually active with somebody (only oral and kissing) and I have been feeling ill over the past couple of weeks. The symptoms were an irritated throat and a mild itch inside the tip of my . I got tested a few days after (pee test, bloodwork and they stuck the q-tip thing in my ) and the doctor also treated with me antibiotics for an STD on the spot just in case, because I was in pain. They never called me back verifying whether or not I had anything which usually means you don't and either way I would have been treated for it, right? So weeks have gone by and my throat was still hurting.. I didn't get a throat culture done, because they told me that the pee test would be able to tell everything regardless. One morning, I woke up with BAD stomach pains, and I even threw up. I rushed to the clinic and when I was seen by a doctor, I explained to them my story and they looked inside of my mouth and told me I had a throat infection...I was relieved to know that something was actually wrong (that could be treated), because I was miserable. He gave me 5 pills of Azithromycin which I used. However, I think the infection had been building up for so long that those 5 pills didn't exactly cure it. I went back and the same doctor told me that I still had an 'ulcer' in my mouth (which he didn't tell me last time). He also gave me a heavier dosage of a different prescription Amox and I'm still taking those and my throat symptoms have gone away, but my stomach is still hurting. I know the pills may have side effects, but I honestly don't think thats it. I even used the bathroom multiple times to see if it was just gas or something, but nope. I haven't been able to sleep, because of it and I've been to the clinc/doctor 4 times this month. Okay, here's my question (sorry it took so long, but I had to give the details) do you think it's possible that since I didn't get a throat culture done I could still have an STD and them not know it? You know your body and when something's wrong. I asked my partner before we did anything if they got tested recently and they said yes. They also said they were tested again after we messed around and were clean..