Istaria, I was in almost the same exact position as you. I used a stone to level my Wiz to 16 and then took a break from the game for almost 6 months. When I came back, it was little banging my head against the wall. I couldn't get through anything without burning through spell points. I was a PM, which is typically cited as one of the best Wiz builds. In a group maybe but since I mostly solo, it just wasn't happening for me.
I did a lot of research on the forums and then respecced to an Evoker AM. My world changed. Emp + Max on Magic Missile and Chain Missiles is awesome. I maxed out the force line and played him like a Sorc basically. On tougher quests, park a cleric hireling with DV at the door as portable shine basically (Natasha the level 16 cleric is awesome, and has Death Ward).
I took Conj secondary for the Heightened Web SLA. Awesomesauce.