I heard of the implantation bleeding so I waited till the 23 and took a test but it was negative

Hi I have a few ?s. I've been thinking I could be pregnant for a few weeks now. My last cycle was nov14. On Nov 25 I had (unprotected) intercourse. I did an ovulation calendar and it said I ovulated Nov 30. On Dec 1 I started spotting pinkish it sometimes had a lil bit of brown or black to it then on Dec 2 it was the same. Then on the 3rd -6th I had a medium flow of like a light red blood. Then on the 7th and 8th it went back to what I had on the 1st and 2nd. I felt nausea all that week. My period wasn't due till the 14th. Well when the 14th came I started to spot again it was pinkish and lasted till the 15th. When I woke up on the 16th I had like a pink watery discharge on my pantieliner. I heard of the implantation bleeding so I waited till the 23 and took a test but it was negative. What should I do?