From what you have described, it sounds like you possibly have (or had) an eptopic pregnancy, which can be life-threatening.
It is possible that you did have a "normal" period becuase the fetus was not large enough, or in the right location, to produce sufficient hormones to tell your body that you are pregnant.
Then, by the time another week had gone by, the fetus was big enough to start damaging your fallopian tubes. This is why you felt like hell and started to have abdominal pains. The most recent bleed could be from one of two things - your body has expelled the fetus on its own and you are experiencing another period, or b) (more likely) your fallopian tube has ruptured and you are losing blood from the damaged tube. The only way to tell which one has happened is to go to an ER.
DO NOT WAIT to see your doctor tomorrow. This is urgent and potentially deadly. You could die from immediate blood loss or from severe infection in a few days.
I wish you the best of luck and hope that you get the medical attention that you need right away. Don't fret about the costs. I am in earnest about the urgency of your situation.
When you have recovered, consider doubling up on your birth control. Especially if you are not in the daily habit of taking your pill at the same time every day. Even when taken according to directions, every method has a failure rate. If you add on condoms, NuvaRing, Depo Provera, gel, foam or anything else, you add an extra layer of protection from pregnancy. By the way "withdrawal" is not on the list. 85% of people who use this method become pregnant every year and are freely passing along STD's without concern for their partners' health, particularly the unmarried ones.
I personally use three methods all the time, and one of them is ALWAYS a condom, because I am cautious about whatever unknown disease we are passing around these days.
Now, turn off the computer and get a ride to the ER - don't drive in case you pass out or can't concentrate on driving!