Spotting, no period. Am I pregnant?

I had unprotected sex a little over 3 weeks ago. I am on the pill, but have been a few hours late on a few occasions. I took the morning after pill within the three days as well. My period was supposed to come around that time. I had some spotting, but other then that nothing. Since then, I have been back and forth with different symptoms (sense of smell, nausea every now and then, peeing on an above average level, sore breasts, moodiness, and discharge, cramping, side pains rarely). My next period is due in a few weeks, but I am wondering what are my chances of being pregnant? Are these symptoms possibly the side effects to mixing the pill and plan B so close to my period? Should I take a test?

Also, my period is generally irregular, so could that be an additional factor to my symptoms?