Feeling sick 🤢 and have a 12 week baby

Just had my baby November an I have been getting my period every 4 weeks and it’s been on track. Currently I am cd13 technically as per the app my ovulation is in 4 days but I took a ovulation test and it’s positive today. I have been super nauseous all day I can’t remember how I felt before I got pregnant during ovulation but I’d nausea normal ? Could I be pregnant again even though I had a normal period 13 day’s ago? We are using condoms but of course it’s not full proof