Period

I'm on the pill and I've been taking it four two years now. I'm not good about taking it at the same time every day but I do take it. I'm getting married in 9 months too. I usually get my period on the third day of taking my placebo or(sugar) pill. I also usually cramp for a whole day before I get it and I am now on day four of my pill and still no signs of aunt flow. I took a pregnancy test last night and it was negative. Could I be pregnant? I'm not having any symptoms at all. If I am is it too early to tell?