Weird sensations in my belly

Hi! I am 24 weeks with my 3rd; though there is a 10 years between this one and my 2nd (!) so while this is all familiar, apparently i have forgotten a lot.. or a lot has changed since I was 25! Baby is moving a lot, which is great, and I am recently feeling so big and round, which is... great. Over the past 2 or 3 weeks I have had several instances where I have this strange flash of sensation in my upper belly. Maybe an inch or so above my belly button, or about two inches to the right. It doesn't exactly hurt, but is this flash of sensation that is uncomfortable; I'll catch my breath and stop abruptly. I can happen if I am moving (reaching, turning, walking, or sometimes just baby moves), and if i press around on my stomach I can find it and recreate it (not my favorite thing to do!). I don't think this is round ligament pain, which I think I can identify pretty well; but I have no idea what's going on! Google search turns up warning signs for pre-eclampsia; which is unnerving but I'm not sure that's it... Any one else ever have this before or have any ideas? I have my next ob appointment next week, but am wondering if I should connect sooner since it's happening almost every day now...