Side effects of Evening Primrose Oil

Has anyone ever had any side effects from evening primrose oil? I️ started taking it last cycle up until ovulation and everything was all good until the day before AF. (No BFP)

I️ started spotting and cramping the day before which never happens and continued to have painful cramps my whole period. But they were different than normal it really felt like my uterus was full of concrete, very stiff and heavy. I️ only really bled for 3 days but I’ve continued to have that old blood sort of spotting for the last 3 days. AF ended on Monday and the cramps have continued. I️ thought maybe it was gas or constipation but I’ve taken meds to rectify both and still cramping. Last night I️ had a couple of sharp pains in my uterus that hurt badly enough to stop me in my tracks. The only thing that seems to help a little bit is a heating pad.

The only thing I️ changed last cycle was adding EPO to my routine. It’s supposed to help with cervical mucus but I’m wondering if maybe it threw my hormones out of balance somehow and that’s what’s made this period strange? Has this happened to anyone else before?