please help me out!!

So, I'm in a bit of a predicament. Last month, I got my period and within the week after words, I had unprotected sex quite a few times with him finishing in me. The last time was the 26th of November. I am on the pill, however, I was manipulating my birth control for the past 3 months to get my period earlier. So I would randomly stop taking it to get my period and then start a new pack. (I know how stupid and irresponsible it is /:) so anyways, it's now December 15th and my period is a couple days late and I haven't been feeling 100%. Granted these symptoms could be PMS symptoms but idk. Is it too soon to be taking a test? Should I wait longer? Is it even possible I could be pregnant? Need some answers, possibly by someone who has been through a situation like this!