Just got out of jail and I'm coming off a 2 week heroin binge. What do I do?

It's a long story really, but I stole a car 2 days ago to get high and I really didn't think I was doing anything wrong. I was going to drop my friend off and come back to my truck and go home, but when I got off work from my job my truck was gone so I stole a car. I came home and 5 mins later the police showed up and so I got sent back to jail and I'm coming off heroin. So I'm wondering what I can do to get off this shit. I'm in jail but I'll probably be out in a day or two. I've been doing heroin for 4 years now and I've been to rehab 3 times and I can't seem to quit. I'm 35 and I'm sick of fucking up. I'm sick of my family worrying about me. I'm sick of my fiance worrying about me, I really am. So I need help. I'll take any advise that I can get. Thanks!