Is this breakthrough bleeding?

I’ve been on the pill for a year a ahalf now but I never had spotting between withdrawal bleeds. Last Saturday I began having brown discharge and since then it has continued a little bit each day with small hints of red. It started at the end of my second active week . Never on my underwear and not enough for a liner. I’m thinking maybe my dose is now too low? Can that happen this far in? I called my doctor but I don’t have the copay money to see her yet. Just wanna know what this is