Breakthrough bleeding--is this normal?

Because my husband and I haven't been having this month, I became a little lax with my birth control pills and accidentally skipped two during the second week of active pills. About 10-11 days before my period's supposed to start, I started experiencing breakthrough bleeding. At first it was mostly just brownish discharge, but now it's a lot redder and is heavy enough to fill two pads a day. I've also started having really bad cramps for about 3-4 hours a day, and today my chest started hurting a lot--not like sore , but sharp, sometimes shooting pains in my chest. This all started about 4 days ago. How long should I expect this to go on, and is it something I should see my doctor about? Ever since I skipped those two pills, I've been taking them religiously every night.