Yo, well first off I thought there was a difference between restlessness and akathisia, but I may have been wrong.
I find that kind of bizarre that it took that long to go away. I guess people experience all kinds of things from different medications/drugs. It would make sense that apart from an initial spike as a result of the shot, it would exit the system pretty gradually.
My memory of that time isn't too clear. I think I blocked it out largely because I not only had very few friends (and those were mostly based on people that felt sorry for me, as opposed to a genuine reciprocal social tie) due to the extreme amount of narcissism and self-involvement that came with my disease; so not only that, but the substance reduced what worldly joy I had considerably. I think this might be something common that people go through.
The first couple months (at least) are not just uncomfortable because one has alienated others and has to face this fact and repair relationships, but also because the drug itself takes a lot of joy out of life, which functionally speaking is kind of good in that it spurs people to find enjoyment around others a lot more than previously. I mean, previously I could basically be totally content sitting in front of a computer all day. I think antipsychotics make it so being a loner isn't as enjoyable. And I mean with all this talk about brain-damage, I think it's pretty clear that the brain doesn't grow or maintain itself nearly as well if one is socially deprived.
I still take psych. meds. I guess the difference is that I did what the doctors told me to do, and as a result am more integrated/happy. I know this probably isn't what you want to hear, but I think it's worth considering. These aren't posted in any particular order, but some were necessary to implement before I could start others.
1. I took the meds
2. I gave each antipyschotic med at least two months before switching
3. I stopped using all recreational substances
4. I engaged in intensive therapy
5. I got to know myself enough (through 1-4) that I figured out what worked for my with respect to dealing with residual symptoms
6. I trusted those on the outside to give me an idea of how I was doing, and took their opinions to heart
7. I became brutally honest with my healthcare providers
8. I made (and still make) it a goal to stretch my comfort zone enough so that I grow, but not so much that I traumatize myself
9. I reached out to people who I used to be better friends with, and didn't take their defensiveness personally
And I'm sure there are others...
I wish I could give you a number, man, but I can't. Everyone is different. I can say though that therapy and socialization are key if you want to feel connected with people and invigorated/substantiated in this life. I can tell you that it's difficult. Getting better is never easy. It will challenge you at your very core. And I guess (in a brutal, if realistic sense) this separates the weak from the strong. I also think that, while it sounds like Invega didn't work well for you, you should consider that medication is meant to accelerate your development, and that it may be hasty to write off all medications because you had a bad experience with Invega.
So true recovery from most things takes time. It involves dedication to yourself, even if it doesn't feel that way in the moment. Worrying about your state of mind in the present, though, will not bode well for that of the future. Start to develop healthy habits, and you have a better chance at feeling the way you want to in the coming months/years. Hope this helped.