Cramping 10 days b4 af

So I just started using glow at the end of last month and I'm 3 dpo and I tested this morning and it was a bfn. I'm having annoying cramps but af isn't here for 10 more days. I currently have a 10 month old son and am ttc for number 2.. With my first I had the same annoying cramps but this morning the test was negative... any advice??