Could I be pregnant?

My

My boyfriend and I started trying to conceive about three weeks ago and I removed my xulane birth control patch at that time and now my period is four days late and I’m constipated for a few days and have been breaking out terribly on my face but I took a test on Monday ($1 one from Walmart) and it was negative can someone help me try to figure out why this is going on? Any help is appreciated.