Help!

Period late by 10 days but have been spotting light brown discharge for the past 4 days and it has stopped today! It is creamy/watery and very light I had one spotting of light red blood but only once when I wiped and then it was back to brown! Had sex unprotected about 20 days ago and not sure when I ovulated, I took a pregnancy test and it was negative! I went back on the jab on Monday also but my doctor said the i shouldn’t get any symptoms for about a week? Last time I went on the jab two weeks later I started my (heavy) period that was bright red, lost right now, I’ve been feeling sick, sore boobs, can smell better and I’ve been getting pretty bad cramps and I don’t usually get cramps... any help and advice would be fantastic! Thank you.