I'm very sorry for the loss of your uncle Ray-Ray Russell and understand he made a significant impact on your life and young career. I myself have lost family members including my mother and understand losing a loved one is difficult and can be hard to overcome.
Not many fans or media members bother to question this aspect of your recent play on the football field.
I still believe you have all the talent in the world, but the usual "rock" in your life has been taken to heaven and now you are kind of spinning out of control making poor judgement calls you wouldn't have made before your uncle died.
I believe you'll make the right adjustments eventually and become the man you need to become, but you need to find someone willing to provide you guidance and/or help to get past some of the feelings you need to get off of your chest. Believe me, I know how hard it is to keep it all inside. My Mom died 2 months before I graduated college and 6 months before I got married. I kept it inside for awhile and made some decisions I know I wouldn't have made when my mind was right.
Now is the time to really overcome this. You need to take control of your life and get back to being the leader you were becoming back in March. You need to try to focus and work on the playbook.
As for the fans, they need to understand where you are at mentally right now. I don't believe you are there completely when you are playing. I think you are getting frustrated too often and aren't staying on that even keel your HS coach taught you. It's obvious when you take plays off because you aren't putting any energy in to your throws.
These are all signs of at minimum the blues and at worst some case of depression that most people who haven't dealt with depression in their lives are able to overcome. It takes time and some setbacks, but I believe you have the mental makeup to overcome everything.
This isn't just a football issue, it's a real life issue that needs to be assessed. It's obviously affecting your play at QB and thus how the offense plays, but it's obviously affecting you off the field.
I highly doubt your current weight issue would be an issue if your uncle were still around. I don't think you would be missing team meetings or being consistently late for them. You wouldn't have been caught drinking in public with eyes that were obviously bloodshot from drinking. Again, these are more signs that you need some help. This isn't the Jamarcus Russell uncle Ray-Ray would like to see.
Talk to Jimbo Fisher or your high school coach. Find someone in your life whom you can talk to about anything without feeling like your embarrassing yourself. There's only a few people I can talk to like this, especially after my little brother committed suicide.
You can overcome your tragedies, you just need to find someone willing to become your wall that you can bounce your thoughts off and get them off of your chest.
Good luck in life, not just football. I believe you have everything going for you and you can become not only the QB but the man your uncle Ray-Ray wanted. You now what to do and how to do it, you just need to trust yourself man.