Oh lovey, believe me, it's really not that bad. Honest.
You did something regrettable, taking the money intending to replace it before it was noticed. That's not the same as stealing it without intending to pay it back.
Yes you let them down, but people make mistakes.
As for letting the cat out about the other girl. Meh. I'd have knowingly told her. Ex DP's mate is the one in the wrong, not you.
Have you repaid the money?
What's the issue with your parents? Have you driven them to this point or are they just not nice people?
If it's your behaviour over the years, then apologise & clean up your act.
If it's them, could you look at staying in a shelter? Or at a friend's?
Work hard at getting a job, volunteer in the meantime.
You can get your life back on track, many of us are decades probably, down the line from you with MUCH bigger fuck ups along the way.