So confused!

I got my period around the same time as usual and it lasted my normal 4 days (oct 1-4) so I assumed there's no way I could have gotten pregnant the last month. Then it ended like normal and week later (a few days ago) I had crampy feelings and I rarely get those and just felt interesting in my abdomen, almost like fullness and mild cramps. Plus I had some very light bleeding the day after sex a few days ago. I decided randomly to just take a pregnancy test and it came back positive I think. See picture. I didn't think there was a chance of being pregnant. Thoughts please? Thank you!!