can you preclampcia with mild symptoms and Not know ?

I didn't find I had preeclampsia till I was due I had really bad swelling at 30 something week but didn't have the high blood pressure and protein in my urine till like 38-39 weeks

I was seeing weired sparks in the shower and recently I've been getting super bad headaches

I had headaches too

Ya you can. The doctor said I had slight preeclampsia during labor and I almost had to get a csection

I had it as well while I was pregnant

what are other signs? I've been getting a lot of headaches and when do they test for it?