mrsshears that sounds very much like the situation my mum had with me - no idea why, but I just wasn't taking on enough milk (I think I was maybe just an inefficient feeder). She switched to ff at about 2 months, and I just flourished. Even now she still feels a bit unhappy about not being able to bf (seeing me bf DS has brought up a lot of memories I think), but it was definitely the right thing to do. Great that you are managing to mix feed though, the best of both worlds, surely? 
I've just been to sing at a wedding and left DS with DH and FIL for 2.5 hrs - the longest I've been apart from him since he came home! It was very odd, rather like a return to my old life, and there was the odd moment when I actually forgot I have a son! 
Warlin I find the bedtime clothing situation tricky too, especially as he often gets cold from around 4 or 5am (usually because he's damp from all the vomit). I nearly always have him in a vest and babygro, because he feels the cold easily, but then he is swaddled in a flannelette sheet with as many blanket layers as appropriate - so only one when been warm lately. He just won't settle if he's not snug and warm.
Little milk monster is now guzzling 4oz of expressed milk in one sitting - I'm going to have to pump a bit more often, as he has annihilated my freezer stash this weekend! But all this constant eating is definitely paying dividends - he is growing at a rate of knots! Weigh in on Tuesday, so I wonder how much he will have gained?