6:45 - WU
8:25 - pd
8:45 S (OT nap)
9:15, WU
10:30 - S
11:45 - WU (UT nap)
12:45 - S
1:25 woke, resettled after 15-20mins
3:10 - WU (2ish hr nap, broken)
4:30 - pd... no nap
6:30 asleep with feed, woke when pd (probably quite OT by this point, so easily woken)
8 - asleep for the night
Alrighty, so I've just translated that day for clarity for me.
Yes, he was likely OT by 2hr A time, hence the 30min nap - its too much for a 3mo baby, really. It will probably be just right in a few short weeks when he turns 4mo though.
You then fell into the classic trap of shortening the next A time too much and he took an UT nap - just slightly UT, mind you. What I'd suggest for him at the moment is 1:40-1:45 A time, with a reduction to 1:30 after a short nap.
Ideally, you would feed him when he wakes from a nap - that gives you both some perdictabilty in your day about what's coming next... and stops the old falling asleep in the middle of A time beacuse he's feeding.
3.10Went back down at 4.30 but would not settle at all, dummy in and out, finally got him up at 5.30 but was happy enough.
So here he had a relatively good nap and then a short 1:20 A time - so he was UT when you put him down and OT by the time you got him up and very OT at 6:30 when he fell asleep feeding and woke when put down.
Give this a go: 1:40-1:45 A time, with a reduction to 1:30 after a short nap; and see what happens. I think if you can keep that consistent for a few days, things should fall into place for a little while.