If you know you can't resist the pressure from your old "friends" -- then avoid them. (I put the word "friends" in quotation marks, because they aren't really your friends if they want to harm you and drag you down.)
After all, your family would be happy to have you spend the whole time quietly with them, and you don't even need to let your old "friends" know you're in town. The Bible's advice is true: "Do not be misled: 'Bad company corrupts good character'" (1 Corinthians 15:33). Eventually, you'll need to cut yourself off from them anyway, so why not start now? Don't risk losing all you've accomplished the last six months because of them; it isn't worth it.
The most important thing you can do, however, is to put your life into God's hands, and seek from Him the strength you need to resist temptation. God loves you; He loves you so much that His Son was willing to give His life for you. Don't try to fight this battle alone, but turn to Christ and ask Him to come into your life -- and He will.
Then find new friends -- friends who love God and will care what happens to you. Seek out a church where Christ is preached and lived, and ask God to lead you to people there who can help you and encourage you. We are never alone when we belong to Christ. God bless you.