Confused on implantation

Lili

Hi, I'm trying to conceive baby#2. My usual cycle length is 30 days and I usually ovulate on 16 or 17 cd. This time around I bd on cd 11 et cd 14. I started to have mild symptoms around 4dpo (some tiny cramps like af ones but lighter) and 6 dpo I woke up with really bad lower back pain and stinging boobs on and off. Thought it was implantation cramps but I'm not sure. 7dpo I woke up drench in sweat. 8dpo I felt like someone bit my right pelvic area hard I had to stop walking for a bit but it went away quickly. Ever since it happened I strongly questioning if 8 dpo was indeed implantation instead of 6dpo. Either way all my symptoms are totally different compared to my 1st pregnancy and not part of my usual cycle, something is up I'm sure of it. Any thoughts ? I'm 10 dpo today, af due in 4 days