if i understood it correctly, you're playing as a mage and this is your first char in dd. it might be a bit difficult for a mage;why don't you play a warrior instead? imo its the best class for beginners. warriors have the most hit pts and damage per constitution and str pt. even then, a warrior will still find it difficult to go toe-to-toe with those damn skeletal guardians, as i found out too dearly with my first character. so i asked around in this forum and i found that their levels are much higher. you can deal with them much easier if you use a bow: run and gun, run and gun. even without a pt in bow expertise you'll get past those tough monsters. just be patient. it's really difficult initially, especially when don't have good gear and don't have a lot of hit points. when you get to rivertown market, you'll find better gear and hopefully, things will start to be a bit easier. now i'm making my 4th char and those skeletal guardians, skeleton lords, skeletal conjurer lords in the catacombs are not much of a problem as before. they're still tough when you melee, even in easy mode, but beatable. just takes a little getting used to the monsters' levels and their capabilities.
on freeze, if you read the skill description carefully, only monsters up to a certain resistance can be frozen per level of freeze. so if their resistance is higher than the level of freeze skill you have, then they won't be frozen. however, when you get out of aleroth and face the orcs, you'll find that freeze will be very helpful, especially against those annoying war drummers. dispose of them firstly and quickly.
for good weapons and armor, what i do is save as much gold as i can. i even keep slasher so i can sell it later if i find a good item which costs a lot. if i can't find good gear in rivertown market, i head to the dark forest. gavanariel, the elven merchant there, sells excellent gear, especially bows and armor, aside from death blades, daggers, axes, etc. save your game before talking to him then just re-load and re-load until you get the item/s you want.
on the zombie guardian gregar brock, i usually save him until i get to the last level of the catacombs. things can get a bit hairy there. hopefully, you would have found scorpion trap to help you, too.
