Implantation bleeding - yes or no!

I have had 2 cycles of femara. The first one was with 2.5gm tablet and second was with 5g tablet on cycle day 3-7. The first one obviously did not work. My first day of period was March 25th and I went for 2 follicular sonogram on Apr 3rd and 4th. One one my ovaries measure 19.2 on 4th April and the doc gave a hcg shot the same day to release egg. We had intercourse on April 3rd, April 4th and April 6th. So I think we caught the correct date. Fast forward to April 11th- I had my progesterone test and the level came was 15. The same day on April 11th which was 8dpo (cycle day 18) I had some bleeding all of sudden - it was bright red and then turned light pink. The bleeding stopped within a couple of hours and there was nothing after that. I had no cramping or no pain. This morning on cycle day 23 I took a pregnancy test and it came negative. Now I am really confused and sort of heart broken. I have no other symptoms of pms or pregnancy.

Has anyone experienced this and went on to become pregnant?

Was that implantation bleeding or just a side effect of the drugs and shot?

Can implantation be red in color?

Was it too early to test? I read you get positive as soon as implantation happens

Please share your stories. This unpredictability is driving me mad.