Conceiving After Miscarriage

I just miscarried our second child on Saturday; I couldn't have been any further than four weeks along -- in fact, I only just got my first faint positive that morning. Now, while my husband and I have/are mourning the loss of this baby, we have decided to try to get pregnant again with no waiting. Originally we figured we would start BDing once my bleeding fully stopped, but I've continued taking OPKs everyday even as I'm bleeding anyway (we weren't entirely sure when my ovulation was with my previous cycles even though the period was regular. Hence, opk everyday). I know that post miscarriage it is common to basically have at least some detectable level of lh most of the time, but this afternoon I got a crazy bold positive on my opk. Then this evening it was faint, like I would expect. Could my positive earlier really be because of impending ovulation, even though I haven't completely stopped bleeding yet (though it has been pretty light this entire time), and it's only 5 days in? Or is there anything else that would cause a strong lh surge? And my hcg has gone down to undetectable by now, if that makes a difference.