Sharpe pain ... Implantation? Advice please

Stes
Hi my cycles are all over the place and are not regular at the moment (so annoying 😟) anyway I think i ovulated about 10 days ago and from days 4-7dpo I have been getting period like cramps... On 7dpo the pain was that bad in the night it woke me up! l thought it was af making an appearance... Still no af and bfn.... Is there such a thing as implantion pains? 
Any advice would be great. Thanks