Hi brother Adam113,
Thanks for sharing your struggles. Reading your post reminded me of Romans 6. It's a great chapter (of many) that identifies our position in Christ as slaves. Verse 5 states, "For if we have been [*] united with him in a death like his, we shall certainly be united with him in a resurrection like his."
* = "we have been" is one word in the Greek. It's a verb in the perfect tense. This tense is theologically rich and significant. Here it describes an objective that was met in the past (salvation) that has been true from the past up to the present time.
I agree with you fully where you wrote, "A huge lie is that one can do what they want and be saved" ---end of your quote"--- Satan used the same lie in the garden –"you will not surely die".
Please keep yourself grounded in the Word of God and be part of a local, Bible based church where the Bible is the authority and not a canned theology.
There are Christian counselling centers that can help with drug addictions. One found in several States is Teen Challenge (not just for teens).
Above all, we need to "keep the faith" (2 Timothy 4:7). Jesus Christ will get us to the finish line as long as we keep looking up, in dependance on Him and His Word. The greatest commandment is to love Him with our all (Luke 10:27). If you are anything like me –the flesh desires to rule over us. But greater is He in us (1 John 4:4). He is worthy of all our praise and honor today and for all eternity!