You feel squishy because you have not enough defensive options. For my taste, you picked too many offensive passives for the state of the game you are at. Look for items with flat health for the moment, maybe.
You could also consider swapping frost wall for flame ward. It’s a good panic button skill.
As an immediate suggestion:
Relocate 2 passive points from Afterglow to Mana Shell in the sorcerer tree. This way you get the +1 ward per second per 10 max mana, resulting in 15 ward/s for you.
Thanks. I am really struggling. Mana is bad as well.