What Causes Abnormally Heavy Periods?

okay so I am on tricyclen lo birth control pill, i often forget to take one or two a month, am married, and not seriously worried about that. I missed one pill by about 12 hours last week. The next day i started to spot and three days later i started bleeding, and it was heavy...I have now been bleeding heavier than any of my periods for almost a week, and my period is not due to start until next sunday, as in almost two weeks from now. I am curious as to why this is. I have also been very sluggish and tired for over a month now, and getting a lot of serious headaches, mostly they stick to the week of my period, but lately they are almost daily. The last weird symtom i have had is that I tried to have a casual drink while out for a meal the other day, I had no more than 5 sips of white wine, when my head started to throb and i felt very ill, had to spend the rest of the day in bed with migrane like symtoms! It has come to my attention that this may be a miscarriage!help me please