First let me say WELCOME HOME!!!
you are with brothers and sisters here that love you and have been down the SAME roads you are traveling and some even rougher roads, PLEASE remember one thing God loves you and as for you messing up...did you ask for His forgiveness?
if so then it's done over and forgotten, you can go to Him with ANYTHING ANYTIME, it's when you DON'T go to Him that bothers Him, He wants NOTHING more than a REAL-ationship with you, He knows your thoughts before you do keep it real
If you remember in the studies it talked about when you fall, what do you do lay there and feel bad or get back up brush yourself off and move on (you look kinda silly just layin there
)
Just keep asking God to forgive you when you fail and get back up and tell satan he ain't gona win that easy!!
Also remember you are on Gods time schedule so just be patient and know He is working on you
As for the drugs (getting high) when you feel that urge go to God and ask for Him to take the urge away that you are not strong enough to resist it without Him ( 1 corinthians 10:13 ) you ask how I know...I smoked pot and tobaco for over 20 years and it controled me until I went to God...I don't smoke either one anymore (tobaco OR pot)
maybe the job He has in mind for you is not available yet, Just keep trying and God will lead you where He wants you.
As for the being lonely you can come here 24-7 some one is ALWAYS here,I know what you mean though human contact, try church, or volunteer
Just don't give up because then satan wins, everytime you get back up or resist, satan gets a little weaker ( I like to think it's like a knockout punch from God )
may God bless you and give you the strength to win this battle
Cuc