HOCD or Gay? Please help!!!

I'm a freshman in college. The initial transition went really well; I made a bunch of new friends, etc. However, my schedule for my meds has been wonky since I got here (I take Zoloft for depression and anxiety) and I missed the first two weeks. I fell into one of my old ruts my third week up here, and that lasted about a week, until I hooked up with a female friend of mine for a couple of days before she called it off. For whatever reason, that helped get me back on track, and things went back to normal. Then last week, I missed my meds two days in a row, and then I fell into another rut for a little bit, but that really diminished about two weeks ago. However, a few days later I woke up with all these weird, uncomfortable thoughts, like stupid random things that pop into peoples heads normally, only I couldn't fight them, and they like burrowed into my brain in a way that really freaked me out. I had random thoughts about suicide in general, and about doing...inappropriate things with friends; the latter freaked me out more than the first, because normally if I have weird thoughts like that I can just brush them off, cause I know it means nothing. But in the state I was in, I began hyper-analyzing all of my thoughts, and searching for reasons for everything. It freaked me out, and now I'm obsessing over those random thoughts. I know I'm not gay, I've never felt any such ideas before, I've dated several girls, only ever been attracted to girl, and it's just never been something that I was concerned about. But now, if I try to think about doing anything physical with anyone, guys or girls, it makes me nervous and supremely anxious, and I can?t eat or sleep. I have no idea what's wrong with me now, and I?m terrified. I can't get the thoughts about being gay out of my head, even though only sex with girls turns me on and the thought of anything with guys does nothing for me; in fact, I tried looking at pics and videos and whatnot to see if I was in denial, and it honestly made me gag and it repulsed me. I've never been diagnosed with OCD, but I'm depressive and have major anxiety problems; this same kind of thought process is what knocked me into depression when I began obsessing over pregnancy scares with ex-girlfriends and the thought of leaving my last girlfriend (who I loved, and was terrified I wanted to leave for absolutely no reason, until she broke up with me). I feel like I don't belong in my skin, and I can't stand it. Please, someone help!