May as well jump in - I popped in to day hi on one of the previous threads but haven't been back since. Dd2 was a Halloween baby, so 14 weeks now and I too have a 3 year old.
Major sympathies on the hospital stay - we've had our own stint in hospital and it was mega hard. She was on antibiotics which have left her digestive system very sensitive, nappies are often very runny and a bit mucusy
Dd also has reflux - the pukey kind as opposed to the silent kind. No meds so far as the HCPS around here seem to want to let nature take its course and see how we are once solids are involved.
I'm dribbling with envy at all of the good sleepers - sleep shot to shite here after about a week of decent performance. She did a 5 hour stretch last night but only because she was in bed with me which is a bit annoying because we have a bloody Co sleeper cot, she just won't go in her own bit!
So tbh I've found this to be a hard old slog of a winter: demanding 3 year old and super high maintenance baby plus winter plus me their mother who is naturally introverted and would give my right arm for a whole day of being alone with tea and books....awkward combo. But I do regularly kick myself up the arse and remember how lucky I am so there's that 
Been enjoying the chat so glad that the thread is being salvaged!