Trying To Conceive, Unusual Period, Signs Of Cramping. Pregnancy Test Negative. When To Test Again?

Hi my name is Anett, my periods due date is 9 of january, but since yesterday i have some pain like period pain. I always get these kind of pain abt 2 to 3 days before my period due. Last month I had unsual period, heavy in the first two days, after so light, after stayed normal for a day and finished earlier than usual (6 days). I am trying for a baby with my partner, I had ovulated on the 24-29of december, and the period i described started on the 13th of dec. i had few signs as cramping, higher body tempreture for two days after ovulation , and i did have sex 3x in my ovulation period. But those signs are stopped since yesterday, and now i just feel a little bit of cramping lower down, but nothing else. I did a test today i know it is too early it came back negative. I was wondering if there is any chance i could be pregnant and which day is the earliest i can take a test again and get positive result IF i am really pregnant. Thank you