Early symptoms?

K

My period is due in 4 days. I have had a headache almost every day for the past week and i am not sure why. I drink lots of fluids and i am not heavily stressed about anything. My first pregnancy i found out before my period because i started having pink discharge 3 days before my missed period. Idk if you can even have signs this early but has anyone experienced headaches before you found out you were pregnant??