Weird start

Alyssa

I normally have a heavy flow on the first day of my period. I used a super tampon and went to change it about an hour later expecting there to be a lot of blood but it was only a little and slightly clumpy. It was a little brown as well. This has not happened before. I’m on birth control so my period will come no matter what. Not trying to spook myself and saying it could be a sign of pregnancy but figured I would see what others had to say. Thanks!