Please tell me calm my tits

So hubby and I have a 13m old son and have decided to start trying for #2, I was on the marina for 9 but took it out bc it was effing up my cycle, so I know I’m not regular but according to my app I was fertile Myrtle last week and the past couple of days I’ve been having, not cramps just tightness, and I’m wondering if that’s an implantation sign or am I just looking for signs? With our son we weren’t trying and I took a test just bc I had a feeling so I wasn’t as aware of my body as I have been this time.