Unprotected sex, plan b, wtf lol

So I had my normal period, made love on 3/13 after and husband did not pull out.. I took a plan b 24 hours later on 3/14. I had light spotting for 4 days starting on 3/22. On 3/28 I started experiencing back pain, bloating, diahrea with everything I eat or drink, nausea, breast tingle, and I have cramps off and on like a period is coming. My sex drive is through the roof and I was getting alot of discharge since the pill but now I'm dry and kind of sore. I took a pregnancy test on 3/28 and it was negative... could I still be pregnant or is the pill just really making my life miserable? Lol