8.5 weeks pregnant and had cyst (4cm). today i have terrible pain in ovary and after pain subsided i had a little bit of brown spotting.cyst ruptured?

Possibly: Your symptoms are consistent with a ruptured ovarian cyst, but I can't tell from the info provided whether you had a ruptured cyst @ 8 1/2 weeks in a previous pregnancy or if you're currently 8 1/2 weeks pregnant. If you ARE 8 1/2 pregnant, seek medical care ASAP. If not, and a home pregnancy test is negative, then a few days of watchful waiting is okay as long as you continue to improve.