Good Morning Dr, I Had My Period Last Month On

Good Morning Dr, I had my period last month on the 5th of May and according to my Period Calendar calculations I should be getting my next one on the 3rd of June, I've got a 28 day cycle. I did the dettol test this morning with my first urine and did not urinate about 7 hours before I did the test and it showed positive but I got a little blood a few minutes ago with light menstrual cramps that is not as heavy and painful as other months. Today is only the 28th of May, can I be pregnant?