Shared custody is tough on everyone, and ideally to start with I'd suggest a 4 day turnaround (or more frequently) so everyone can get used to it. I'm not at all convinced that 50/50 is ever in kids' interest, it's about being "fair" for the parents...but I do worry that it might mean the kids don't feel that they have an actual home...
my XH (abusive) is fortunately too preoccupied with himself to want our DC that much, but I struggle when they are with him for more than a few days/nights; OP make yourself busy, even if you don't feel like it, get out and see people/do stuff...anything that stops you sitting at home missing them.
You will eventually find that you get to enjoy your "me time", or at least some of it; I can't say I enjoy all of it, but I do look forward to a certain amount now, and arrange to see friends or just catch up with stuff that could never have been done when I had the DC to think about. It has also, strangely, freed me to be a better mum - I'm much less stressed than when he was here, much more able to think "to hell with the dishes" and play with them...the house is a tip but I don't care, I just enjoy being with the DC when they're here.
You may well find that the reality of having them that much is too much for your X, it happens a lot...so be "helpful" when he wants you to help by having them more and if he's anything like my X he will gradually want them to spend more time with you so he can get on with "his" life...
Best of luck love, you ended your marriage for good reason I'm sure, but I know this is hard to cope with 