12dpo and unsure what to think

Clar

The initial dpo i had very sore/swollen boobs, constipation, cramping.. 11 dpo I got nauseous in the morning and felt normal all day.. then in the evening I got some back pain/cramping and some slight twinges. I’m 12 Dpo and I’ve tested with the strips and no pink line. Not even a faint line. I’m 3 days from my period. Today I keep getting waves of cramps and now nausea. Has this happened to anyone and still got a positive test before?