confused by spotting

Hey All! been TTC x4 months, going into month 5. my cycle this month has been different and has me all sorts of confused. I sometimes spot a day or two before AF is due, pretty regular cramping and my stomach is usually really off. this month, however, my stomach is fine (AF due 1/17 or 1/18), not much if any cramping, my breasts are a bit tender. what's throwing me off is the spotting. I've been spotting since last Monday. a few days it was just light light brown/pink then I didn't have anything for a day then it was back. Friday, I thought AF was starting because it was a lot of pink when I wiped and then it was gone. no spotting Saturday, light brown spotting Sunday and Monday. I thought AF started again this morni g, when I wiped there was a lot of pink but then I've gotten nothing but light brown the rest of the day. I am 12 DPO. I've taken multiple hpt and I don't even get a faint line. has this happened to anyone? what is going on with my body!?