Help, period lasting for almost 4 weeks now.

Recently, I went on birth control during my period. Because my period was lasting for 3 weeks, I went off it. Now it's super heavy again and going on 4 weeks. It's been two days since I last took it, if I took it again would it make me bleed for 2 more months? Will my period ever end or is it likely that i'll be on it for over half a year?