Hehe, nice strategy Foster.
I've also only done this at higher levels and had no problem.
Just a quick tip in case you didn't know, H3lliN: Try not to use too much time and effort on the summoned creatures, as they will disappear when you kill the guys that summon them.
And also the standard tips: Try to sneak up on them in the darkness. If you can get in a hit before they detect you, you'll do more damage (6x for blades).
Use enchanted weapons. A blade with a simple 10 fire damage makes quite a difference.
Make some poisons and use them on your bow and/or blades. You should be able to make poisons even with Alchemy skill below 25 I think.
And remember to block!

Oh, and one more thing: Summoning creatures yourself is very handy - even the weak ones, as they distract the enemies. I think you should already have gotten the summon skeleton spell by now, or...?