You just spoke a thousond words then
Worried, irritated, pressured, unappreciated, etc

She made you feel like that most of the time.. yeah the only reason why the good times stood out.. was because it was a rare thing.

You are better off without her and yeah don't judge your current girlfriends on the mistakes of your past.
Because its not fair on them or on you.

Yes stand up for yourself yes don't get walked over.
But always be a bit understand.

Best of luck