My kids were 3, 4 and 10 yrs. Now they're 14, 15 and 21. Wow.....that looks even worse in print! Anyhoo..... I was pooped in the beginning too. It's an adjustment for sure! I found the isolation hardest. However, once I got used to the new routine, it was totally fine. Now it just feels normal having a houseful of young kids. In fact, I just had a slumber party this weekend with 3 of the girls I used to look after....they're all older now.....that looks worse in print too.
Okay, before I succumb to the ravages of age completely.....Hang in there. It'll get easier. Have stuff (grown up stuff) to look forward to in your off hours. Heck, even during work hours! Set up a coffee date with a friend who has kids. Take the kiddies out for lunch or to the mall. Plan a nap time to do NOTHING!!!!! Plan a 'Sloth Day' with the kids (movies, jammies and buffet). My own children thought it was a national holiday, though it was just my way of doing something fun, different and giving me an opportunity to vegetate for a little while.