Has anyone experienced fertility challenges after having baby #1?

I've always had regular 28-29 day cycles, always! Last month went a week late and now this month AF arrived a week early, Cycle day 22!!!
I was approx 7 or 8 dpo and thought maybe implantation but the cramps are very painful, sharp & constant with medium bleeding and this is going on day 2. I normally only have AF cramps right before it starts and then they'll go away. This is so not normal for me!!! What could this be?!

Should I be concerned about this? This AF almost feels like what my PP bleeding felt like it honestly doesn't feel like a normal AF.
So confused!!!! Any advice?
I am still bf-ing my 2 yr. old, could that effect fertility?!