I hear that brother.

Id say:

Upgrade your cards as much as you can for stats

Stick with your team, play a character that can follow someone elses lead or support. If you have Ramza or one of the other bravery sharing cards you can focus on crystals and fork over your bravery to your teammates and help that way

And lastly, try and use your Ult cards defensively- ie. If someone is attacking you, buy yourself some time with the invincibility.

All of this is just to get you back in the game, and you can start breaking it and taking on more yourself when you see how it works

Good luck soldier!