Did you level up your sword and shield with a greatsword instead of a Wand while you were leveling because it was easier? Here's a build that will let you start tanking now without undoing all your work.
This build is designed to generate good aggro on mobs, drawing them together. It is most effective when targets are getting icebound, so builds that weaken with frost are very compatible. The build gives up mobility, but changing out guillotine blade, death blow, or shot at victory would reduce damage and allow you to add some mobility skills while keeping good aggro, or you could change out stalwart bastion if you aren't worried about defense. You should have no problem keeping single target aggro as well.
we unlock aggro skills early, and the frost variants on DaVinci's Courage and Gaia Crash to create aoe aggro. DaVinci's should be used first.
For best effect, tanks should pull, it is hard to pull large numbers back together, but you should be able to gather them up in a few seconds if ppl are patient.