Hi There

I know this must be really annoying but I’m a little confused about something and I just want to put my mind at ease about it. About 3 weeks ago (12 June) I had unprotected sex with my boyfriend, we used the withdrawal method. Prior to that we had unprotected sex and I used the plan B pill. Yes I know it wasn’t one of my brightest decisions to go and put myself at risk again. Anyway I’m on the pill however during that period I didn’t take it at the same time every day. Last week (20 June) I got a lighter than normal period it wasn't spotting though, when I usually get very heavy periods. This past week I’ve been feeling slightly nauseous and tired with some slight headaches. I took a pregnancy test this Sunday past…it came up negative. I just want to know whether the light period was as a result of the birth control pills as well as the morning after pill being used together and if the symptoms I’m experiencing now are a figment of my imagination or do I possibly still have a chance of being pregnant which brings up the question of whether I should test again?. I’d really appreciate some outside opinions.