When should I test again?HELP

Cher
On Friday night I had a headache and was nauseous so I laid down.I woke up three hrs later ate something and threw up all over the place like 20mins later.After throwing up I slept like a baby.I woke the next morning feeling good.People kept asking me if I was pregnant so I went to test and recognized some bleeding in my underwear so I figured it was just my period.But everyone kept asking me if I was pregnant so I tested.
The test was negative.
This morning I have a headache again and still feel nauseous( which I usually have when I get my period,but this nausea might actually make me throw up). I went to the bathroom and there was no blood on my underwear or the tissue so I am wondering if this is implantation bleeding and if so when should I test again??my cycle is very irregular and I have PCOS so I don't know my dpo,Jan-March my period came the 4 or the 6th but nothing came for April 😒.