Never felt this way....

I woke up feeling terrible today!! I feel nauseous, some cramping, very bad headache, I feel like crying from how bad I feel. My period was from the 19 to the 23. I had sex that same night and again 3 days later. I know testing would be the only way to find out, but since my period is irregular, I'm not due for another 30-35 days, I wouldn't know when to test. So could these be early symptoms IF I were to be pregnant!?