Woman's advice am I pregnant, how can I tell early?

So yeah I want to know why I’m semi-bleeding two weeks before my period is due. I’m real real tired and real emotional, even more emotional than when I am around the time of my period. I’ve felt nauseous early afternoon everyday this week and actually got cramps yesterday and actually got sick on tuesday, and neither one of those normally happen to me at all ever. I’m real hungry but I just ate, and I must have peed a dozen times yesterday. My boobs feel all weird, so does my stomach and head. Normally I’d think, oh its pms but it’s may 7 my last period was april 21 and I am bleeding, a little, I guess Its spotting, only it is not enough to be my period and it would be way too early to be my period anyhow. I had sex on the 1rst and the 3rd of May I believe. I’m not looking for lectures, or insults, and I know the withdraw method isn’t exactly accurate but that’s what was used. I don’t want to think I’m pregnant, but I was at a party last night and a friend had randomly asked if I was because of the way I was acting I suppose and now I just want to now how I know for sure if I am pregnant or not as soon as possible because I can’t buy a test this early I’d have to wait two weeks and I have prescription medications that say don’t take if pregnant or thinking of becoming pregnant but there’s no way I know of to tell if I am or not this soon and if I am pregnant I don’t want to be taking any of my medicine, but if I stop taking it as a precaution until I find out whether I am or not someones going to notice and think somethings up. And I’m not all for needlessly worrying him or my parents when in two weeks I can take a test.