What Causes Bleeding, Breast Soreness, Sickness, Tiredness With Excessive Eating?

Okay. This is quite difficult to explain so I'll give it my best shot. I started taking the pills before my period was due, I started taking them on Wednesday, and the doctor explained that I would not be protected the first week against pregnancy when I started taking them. But unfortunately, things didn't go to plan, and the Friday onwards, I had unprotected sex, a lot. With my partner. I finished taking the pills 21 days later, my last pill was on the Tuesday. I didn't get my withdrawal bleed till Sunday, and it's been very light. When I used to take the pill. I would always come on on the Thursday and it would be quite heavy. No sore boobs, no sickness, no tiredness. No excessive eating either! But the past few weeks I've had all of these :S I've read that sore boobs should have gone right now if it was a symptom of the pill. That you won't bleed because your womb is catering for a baby. That some women do bleed. That some women have had bleeds all the way through they're pregnancy. So I'm very confused. I know it's not a period, but I've heard you can bleed. If I am pregnant I must have concieved around the 19th of February.