Off and on cramping 6/7 dpo?

Well to begin I confirmed O with a positive opk. So yesterday at 6 dpo throughout the whole day I've been having pinching feeling cramps on left side off and on all day. Now today at 7dpo I'm having what feels like a sharp pinching feeling on left side on and off and lower left back pain. Also my breast are very sore and feels like a burning sensation in my nipples and my bra is killing me when it rubs against my breast. And last night I had insomnia which is very rare for me. Could I be having implantation cramping? Anyone else experience this and get there BFP?