Bleeding while on birth control

I am on lo loestrin birth control and have been for about a year. I stopped getting my period on it which my doctor told me was normal. Today I have very little bleeding but I noticed it when i wiped. It’s not enough to need a pad or even anything. Should I be concerned? Also, i am in the middle of the pack right now and this is not the time i would be getting my period even if I did still get periods.