Had period but still have sore breast and cramping

Hi, I was late for my cycle it came on ever so light the first day heavy the second and pretty much done the next. My question is is there a chance that I could be pregnant? My breast are very tender still and I am still getting cramps and a stiff and sore back at times, I am tired, however that is all the time anyways. I was up half the night last night with a very sore stomach and I was nauses today and alittle dizzy (having other issues with that can't tell if its this or that) I took a hpt and came out neg wondered if it was to early to test even after the period maybe have to wait for next month if nothing is back to normal by then. Can you guys give me you thoughts please.