I don't see anything abnormal about that. Literally everyone does the same thing. We use our internal voice or brain to think and rationalize situations in our lives. We weigh outcomes and think about the past and the future in our minds. This is totally normal. All you're saying here, is that your internal dialogue needs to be a little more uplifting and not so judgmental, especially on yourself.
Literally everyone "lives in their heads". Everyone thinks, talks to themselves in their minds, observes situations, weighs pros and cons, thinks about their feelings, fantasizes - these are not abnormal at all.
People are not going to sit on a park bench and spew their entire mental dialogue outloud for everyone to hear.
Just talk to yourself more positively and not so negatively and do not convince yourself that something is wrong with you - that's the negative talk talking.
You're probably just an introvert too, and not an extrovert.
You don't have to be distraught about this unless you want to be, because its totally normal.
By the way, pot makes tons of people paranoid.