Curious about ovulation after birth

(Posted this in another group also)

I saw somewhere that ovulation test can be positive when you’re pregnant and a quick google search showed that could be true. Two weeks ago I had a late term miscarriage at 15 weeks and I was induced so I could have the baby at the hospital. I decided I wanted to try again and so I bought tests to start tracking ovulation and I was wondering if anyone has had experience ovulating so quick after “birth” I know I didn’t technically get to 40 but they did classify me as post partum at the hospital. Could this be leftover HCG or would that be gone by now?