Questions about my rushing, so far

[Floppage]

I've been to 5 fraternities. The first one, I went out to eat with the president; he invited me to a party but I said I couldn't go (I really did have a prior obligation). I haven't heard from them since. The second one, I got a brief house tour, prefunked with some of the guys, then went to party. I haven't heard from them since. The third one, I just got a house tour and talked with the president. I have heard from them since. The fourth one, I just sort of hung out there last weekend and then again during the middle of this week. They'll probably be inviting me over soon, though I'm not that interested in their house. The fifth one, BBQ and hung out last weekend. I thought they'd invite me over again this weekend but they haven't yet (Yes, I know it's only Friday). Another place called me about coming over last weekend; I said I was booked and to call me again, but they haven't yet.

If a house doesn't goes a week without calling me, should I just assume they're not interested? I'm not the kind of dude who likes to invite myself over.