Cramps?? Cautiously optimistic...

Yesterday (and the day before) I had these weird cramps on my left side pretty much lasting on and off most of the day...my period is due the 16th, but I never get cramps! Decided not to use opk’s this cycle as I felt like I just needed to “see” what happened... could it be implantation (not sure when I ovulated this cycle)... or are these cramps just pre-af?

Or am I being too optimistic?