What happened to my sleeping angel?!

I've been pretty lucky with Dominic. The first few weeks of course he was getting up every 2 hours on the dot to eat, but after that they quickly spread out and I was only getting up 2-3 times throughout the night. He'd sleep from about 9pm to 9-10am with getting up just 2 or 3 times. By two-two and half months he was sleeping from 9-10pm until anywhere from 4-6:30am and then would sleep again for at least another couple of hours. I felt so lucky! He did this for a few weeks.

I came up north to my family's favourite vacation spot for almost a whole week, since when I'm working I can usually only manage a couple of nights and wanted to take advantage of my time off. But Dominic doesn't seem to be appreciating the time away! He's been going to bed either later or earlier than usual and is up by 1am, then again at 4am, then again at 6:30 (which if I bring him to bed with me he'll sleep till 8:30 - so this is what I've been doing every night now!). I'm hoping its just because we're away and he's not used to the surroundings. I really hope I haven't changed his sleeping habits now and I'll have to be getting up all throughout the night again!

I have so many worries about him being sleep trained properly and I know I've broken so many cardinal rules. Put them down for naps (I frequently hold him rather than putting him to sleep), I breastfeed him to sleep (a big no-no from what I've read!), I rock him to sleep when he doesn't seem to want to stay asleep when I put him in his crib, and I give him a soother when he wakes up just after being put in his crib (which instantly puts him back to sleep). I hope I have the strength to start trying to sleep train him properly!