Implantation bleeding

I have been trying to get pregnant since I found out I have pcos in February. 4/14 I started spotting then 4/15-4/18 I had a normal "Period" then 4/19 to today 4/23 I have had off and on pink spotting (one time brown) I also feel nausea today. Have some pain during sex not much. ( Not sure if that's because we been trying more) I read exercise can cause spotting but right after u work out. I started working out 4/10 and only 20-30 mins a day, but my spotting isn't right after working out. Is this implantation bleeding and if so when should I test? Google says 3-4 days after bleeding but I've had it 4 days now??