You may have had one or two close friends before you had children, or you may have had eight or nine. No matter how many you had, you likely didn't seem them properly for quite some time after you became a parent. Your child became your whole life. You occasionally worry that they've forgotten about you, so it's always nice when you're invited somewhere.
Getting the invitation doesn't actually mean you can go, though. There's the logistics to think about. Is a babysitter available? How long can the babysitter stay for? What needs to be done to get your child ready for the babysitter before you go out? There's so much to think and plan that it becomes exhausting. Get used to canceling and forget any notion of turning up to anything on time. Hopefully, your friends will just be happy you showed up at all.