Why should I regret something I deeply enjoyed? We all know already that life is a fluent process and sometimes good things happen to change in a way, you don't want it to. But this is how life works:
Things change - People change.
It doesn't necessarily mean that change is bad but of course, it can mean that you are not content with it anymore. Accept that it may be time for something new!
You have to leave the old behind, you have to find something different - something that makes you happy again.
Don't be afraid to be called a quitter. It is not coward to be open for new things - to leave old things behind. It is brave to be true to yourself and recognize when it is time to move on.
Be brave enough to stop when you know it is not what you wanted anymore.
I would not call it giving up - I call it progress!
And progress happens all the time.
Don't regret the moments with the one you left behind for good. All these moments made you the person you are now!
Keep the good memories and be confident to look into a bright future.