I only have the time to enter into one self-help program or therapy group: should I start with the tildes, or with the grammar?

Neither. I think you should help with absent apostrophes. Words that SHOULD have an apostrophe in them, but dont. ;+

In the psych world, that'd be called co-occurring conditions/ dual diagnosis. It's really common for people with any addiction to have an underlying condition. Oftentimes, the individual is "self-medicating" to treat the condition or the addiction is somewhat of a symptom. For example, someone might turn to alcohol or street drugs because they have depression, anxiety, BPD, bipolar disorder, and so on. They could go in and have their addiction treated, but their odds of long-term sobriety is low because they still have that thing in them that caused them to turn to an addiction in the first place. Ergo, identifying any/ all co-occurring conditions and addressing them all at once with a comprehensive plan is the only way to go if you hope to make the treatment stick. 

I'd rally hate to see you doing grammar after investing all that time and energy, and goodness knows that it would only be a matter of time before you'd be back on the street scrounging for tildes again. For your sake, and for the sake of all who care for you, you'll need to work with a qualified treatment center that will address everything, so you have a better chance at long-term success. 

With that in mind, I've made some arrangements for you. These nice men will gladly take you to a place where you can focus on getting totally well.