Confused

I'm on the pill and I'm good when taking it, like I don't miss days etc 
Last last weekend me and my boyfriend had sex without protection but he pulled out, though straight after he asked if any had gone in me
Things were all fine except this week I've been feeling sick most days, on and off, had headaches, had small cramps and been feeling dizzy
Do you think there's any chance I could be pregnant? Like I don't think there really is but it's been an odd week and we're both quite anxious about it