When to take a pregnancy test? Would it be too soon?

I'm 18 and two days after my last period (Nov. 16th), my boyfriend and I fooled around (the first person I've been sexually active with). No sex but while we were being very careful, I feel as maybe something may have happened where I got pre-*** there, even though he has promised he was careful. I know the chances are low, but the chances are there all the same. According to my period tracker, I ovulated the 22nd (and I felt I had ovulated around that time). A few days after our fooling around, I had suddenly gotten on and off nausea and headaches, which I still get now but my boyfriend has said it could be my eyes because my eyesight is really bad and my glasses are out dated. But I've also had off and on dull cramping for the past month too, as well as dull or sharp pangs on pain on my sides, hip bones, and lower back (lower back a lot less, mostly hip bones and sides). I'm on my period right now, my fifth day and on time, but I've read you can bleed during pregnancy too and that some women can have a 'period' while pregnant and this one is slightly different than my normal ones only because the flows are different and I've had more cramping during the period which has never happened before. I've no other symptoms besides the cramps and occasional headaches and nausea (which aren't bad enough to make me feel like throwing up.) I've also some pangs of pain in my breasts, but not sore or tender. This is, I think, normal for my period though. But, being worried, I want to take a test just so I can calm myself and be sure. Would it be too early to take it now? Would it be best to wait? Does it sound like I'm overreacting? Or could I take a test sometime this weekend and be sure?