When’s the earliest you can test for pregnancy?

So basically I ovulated on the 30th December, I am currently taking clomid 50mg CD2-6. I’m on day cycle 26 today and I cannot tell you how awful I’ve felt the last 4 days.

Cramps and twinges in the sides, bad migraines and headaches, blurred vision, sickness feeling on and off, I was sick today at work as I’m a carer urine and poo never normally bother me but today I just couldn’t stand it felt so sick, metal taste in my mouth and nose feels funny, Lower back pain and tender stomach, also a lot of mucus which ive never suffered with before?

Do you think this is a side effect of clomid? Or early pregnancy?