Suggest Treatment For Brown Spotting With No Regular Menstrual Period

hello, so i was suppose to have my period 5 days ago but it never came. three days ago i had light pink to tan blood that i noticed when i wiped but then it went away quickly. yesterday i had brown discharge that was very light as well but has now stopped completely. today i noticed thin, bright red blood when i wiped but this only occurred once so far. i took a pregnancy test this afternoon as well which was negative. i've been taking loestrin 24 fe for almost two years now and i've always had a period so missing one and then having this happen is not normal for me what so ever. is their any advice you can offer me about this situation? thanks.