Hi, Ramsey.
Welcome to SR!
And congrats on 5 days sober and decision to quit for good.
What you call "evil brain" is addictive voice (AV for short ) - something that want you destroyed and dead. Don't listen to it. Ever. It will tell lots of BS. Ignore.
As for the girl - hard to give advice about relationships, but IMHO, sobriety is Number 1 priority now. It is about saving your health and life in the long run. Early sobriety is stressful as it is along with other life issues. You surely don't need additional stress right now.
Again, in my opinion, working on yourself may be a better option.
Best wishes to you.