I started taking birth control pills again when my period started but its been 19 days later and my period hasn't stopped yet. what do i do? cyst?

Wait it out: Sometimes it can take awhile after starting or restarting an oral contraceptive to have your cycle regulate. I would give it 1-2 more months before you consider switching to another birth control pill. Doubtful that it's a cyst on your ovary as this wouldn't cause abnormal bleeding. Women with endometriosis or adenomyosis can have excess bleeding, but, again, birth control pills is the treatmen.

Keep going: Some women will experience 3 to 6 months of irregular bleeding when starting the pill. If it is constantly heavy, you might to seek a change in your current pill. Otherwise ride it out. Your period will usually straighten out and be regular. Good luck. It is probably not a cyst.