Ovulation tests (OPK) detect LH, ahormone from the pituitary which spikes to cause ovulation. Hcg is very similar to LH, so the OPK can't tell whether it's hcg or LH present in your body.
So as long as you have elevated hcg, you can have a positive OPK.
It's possible to ovulate with an elevated hcg, but it's less likely, since the hcg inhibits ovulation.
So it's most likely that you haven't ovulated since the miscarriage. It would be best for you to wait until your hcg is back to normal (less than 5) before trying to get pregnant. Most likely it will be <5 within another week or so. Best wishes.
You usually won't get a normal period until after you ovulate.
You may have some bleeding or spotting, as you have, but that's neither a period nor likely to be ovulation bleeding. It's either left over from the miscarriage or due to some buildup of the uterine lining due to hormones from your ovaries.
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