Please does anyone know roughly how long periods last when your on the pill, I missed one pill, came on my period and the whole reason I went on it, was so I wasn't on this weekend, I came on on Wednesday and I'm still on now, I can't be on this weekend/next week! Please help me!

Missing any pills could result in pregnancy and period. As for stopping there is no was of doing so unless you get the pill with a few times a year periods. The body is doing what it does naturally.
I even know a few people who continued to get periods on the pill taken properly. You may want to discuse with your health care provider About a stronger dose pill that seems to help some as well.
Best of luck