You'll go through at least 2 more transitions like this before you're 28.
And, if you think you're on the right track, you're prolly wrong. You were on the "right track" before. Luckily we, as humans, are blessed with not knowing what is truly a "right track". Instead we are guessing and blindly taking paths that seem right to us at that moment.
And remember that everyone has to do it, no exceptions. Knowing that you'll be more empathetic to other's struggles, such as your girlfriend.
I've said it before many times, we all suffer. No one is exempt.