Im scared to death ! Another period?

Okay i had my period May 6 and then yesterday I started lightly bleeding and its red ! it isnt heavy at all... it stopped for a little bit yesterday then this morning I started bleeding lightly again? I also have tiny cramps with it? I also take birth control and missed 2 of them last month and 2 this month. Is this normal ?!!?! Im scared ! And never did this before and I had a regular cycle ? What is this ?! i never had sex.