Implantation bleeding or not

Hello been Tring to get pregnant for 5 months now I'm fairly regular aswell but the other day I had abit blood and won't have my period till 23rd April and I'm very confused it was alot more pink for an hour or so and then went to what the picture is, not ovulation as I've already ovulated and I've never had that before and I also did an ovulation test that day and it was negative I'm so confused help never had this happan at all and not an injury lol as I'm not in any pain but nipples are sore and I've had abit of pelvic pain but was pink the night before of this picture thankyou