COULD BE PREGNANT! QUESTION? NEED ADVICE.

Hi Ladies I'm TTC and on March 5 2018 was my highest ovulation day then on March 10,2018 I started having cramping for about 2 days then it went away. My expected period date was not till March 20, 2018 so it was to early for period cramps. Took a pregnancy test on March 16,2018 it was negative. On March 17,2018 I had brownish vaginal discharge when I woke up. Then later in the day it was pinkish discharge, on March 18,2018 it was red when I wiped on March 19,2018 it was red again when I wiped On March 20, 2018 it was red when I. Wiped till about 9pm then it was pink when I wiped. Now I woke up at 3am on March 21,2018 to go pee and it was pink when I wiped. It's very strange first of all because I never get cramping 10 days before expected period and I always bleed heavy for 4 total days not just 2. So I'm wondering if I am pregnant and it's just came up negative because my HCG levels were to low to detect. Advice here please. Thank you 😊