Scared I might be pregnant!

I just turned 19 and am on birth control, but my period is 4 days late today. I got pregnant around this time last year, but it ended in a miscarriage. (Is it bad to say I'm almost glad I didn't have a child?) I'm terrified that I may have to go through it again. I just lost my home and I barely make enough to get by at a pizza place. I'm terrified.