Need some advice please!

Ma
I had some light bleeding for less than 48 hours light pink and with mucus in it on and off throughout the day mostly when I used the restroom. I have also had pain in my uterus area also have had dizzy spells. I am 12dpo. I wasn't suppose to get AF for another week. I normally take meds to get AF since I have an irregular cycle but I didn't take the meds to even get it this time. My cycle is about 39 days long. I called a nurseline but right away was told this was AF. I did a test yesterday but it was a BFN. The Dr suggested I take tests for the next 3 or 4 days but I'm afraid to do so because I don't want to keep on being disappointed. Any suggestions? Anybody have this happen to them before?