Sorry to hear it wasn't a great night.
Don't know if it helps but DS has a 12 hr day. I did do a couple of EBTs when he first dropped the nap but very quickly we got into the routine of 12hr (ha, that was before the routine messed up with clock change but we are back on track now). Some EWs, some very odd late mornings (he doesn't tack on in the morning so a late morning here is highly unusual) - but he still sneaks micro naps in the car (eg about 3 mins yesterday just before we arrived at the shops), I think they are more of a hindrance than a help now but the first month or so it was useful, I know you don't have that option though.
I've done 5.30 BTs too, often with good results.
Good luck!