Hcg rising after miscarriage

Marlee • Married💕 5 year old son💙 21 month old daughter🌈 🤰 with #3🌈

Someone please help! I’m so confused. My husband and I found out we were expecting our 2nd baby the beginning of this month. Last Tuesday I woke up bleeding. Went to the doctor that day and had the confirmed miscarriage. She could see blood with an ultrasound consistent with a miscarriage. They took my blood that day and my beta hcg was at 17 also consistent with a miscarriage. Told me to come back in 1-2 weeks to get blood taken again to make sure it got down to 0. So yesterday I went in and they called me back today with results. My beta hcg is now at 64. What’s going on? I’m also taking ovulation tests right now because my husband and I were planning to try again right away. The ovulation tests are positive today. Has this happened to anyone? What was the outcome? What could this be?