Skills were in my twenties back then as well. And yes, melee is the way, arrows don't do much against Yagluth. Use Frostner, be quick on your feet, always have a fire resist potion in you and hammer that bastard.

Tip: I used the "Fingers" around his altar as temporary protection against his meteorite shower.

Also, always have a few medium health potions on you, just in case. Fight can take two in-game days and one night.

I died two times, but could finish him. I think best armor for me was padded with the fenris tunic for negating the speed penalty. This allowed me to escape his nova and other shenanigans.

Oh, and have everything at least upgraded to level 3.

One more thing: Food is very important (as throughout the game). Get the best you can.

In regards to your world saves... the new patch should aleviate that a lot. I also would HIGHLY recommend to turn OFF Steam Cloud save. Move your character and world to local on the main menu BEFORE you do that, though!

Once Steam Cloud is turned off, the game should run (fairly) smoothly.