Implantation

Hello ladies I’m new here. I got my bfp on the digital 3 days ago and am now 4 weeks. I started to spot/light flow with pink/ brownish when I wipe. I’m freaking out!! Everything I have read said at 4 weeks you may have implantation bleeding. I wanted to know if anyone else has experienced this and still had a healthy pregnancy #1 and #2 once you implant how many days can it take to fully embed into your uterus? I’m wondering if this is the reason for the bleeding. I do have very light cramping on and off but pretty heavy back pain. Please ladies say a prayer for me🙏🏼🙏🏼🙏🏼🙏🏼🙏🏼🙏🏼🙏🏼