Clomid and pregnancy

Hello everyone. I've tried to post before but never got replies back and would like some feedback or hoping for feedback this time.

I have been trying to conceive for a year now after a miscarriage. My doctor put me on a 50 mg dose of clomid I took it days 5-9. My period is due in a week and for 3 days I have had nausea all day, lower back pain, and a headache. Are these early pregnancy signs or just the medicine causing me to feel this way and my period on its way.

Also of anyone has taken clomid did it work for you?