I've been on the mini-pill (desogestrel) for almost 5 weeks and just started spotting on the first day of my fertile window.

Since I became sexually active for the first time my cycle changed and began a week earlier, but up until now my periods have still been regular and birth control hasn't caused me to bleed at abnormal times until now.

Last weekend I took my pill half an hour earlier than I usually do, and within 24 hours I had unprotected sex with my partner and let him finish without withdrawl. I understand I have some leeway with what time I can take my pill, but how much less effective is it if i don't take it at exactly the same time?

Could it be implantation??

Just to be safe I'm going to take a pregnancy test in a week or two, but I always appreciate a second opinion :)