Becoming a parent is a HUGE transition and often, we don't deliberately take the time to mentally adjust to the change.
We get stuck in identifying ourselves with the past and what life used to be like, but the reality is (there's that bloody reality again, lol) that life HAS changed and it CAN'T be the way it used to be.
You need to let it go and instead, focus on what you want for your life NOW and how you can fit it in around your kids.
Too often, we focus our attention on what we're missing out on and I'd love a dollar for every time I've asked someone, "So what would the ideal be? What do you want?" And they've said, "I don't know".
Umm, well, how can you possibly expect to be enjoying your life when you keep looking for everything you don't have but have no clarity on what you want?
Who do you want to be?
How do you want to construct your life?
What sort of parent do you want to be?
What experiences would you like to have?
Once you've established that, then you need to follow the great advice that a friend once told me:
"You decide what it is you want to do, then you plot and scheme around your kids to do it."
The only reason why you feel you've lost your identity is because you are still trying to identify with a you that doesn't exist anymore. Life has changed. You need to move with the times and get deliberate about life.
ps - for more reading on this topic, check out my book 'A Parent's Guide to Finding Your Lost Identity' and Discovering your personal peace.