Im having trouble defeating harder enemies/groups of enemies while dual wielding or using magic, my hp and mana goes down insanly fast and i have to resort to using potions...which i hate using because if i cant win a battle without em i dont feel i defeated em "fairly

Wards, or an armour buff.

Well, it's hard to say since you're not really giving much insight into your build, but it sounds like you should increase your overall health and invest more into defensive perks (not blocking, obviously, since both your hands are occupied by seperate items or magic).

sword in one hand healing spell in other, I do have almost all the swords perks though that makes it do twice the damage etc if your low on hp I back away and duel wield two healing spells and get hp back to full. Seems to work for me

This isnt world of warcraft where little kids duel you and ask you not to use your pet, potions and heals. Do what it takes to win.
Duel wield is imo all about offensive.

Dont mages have shield spells?

Sword and board.

Two handed can block as well

I just upgraded my armour and got good at dodging (just quicker with the thumb sticks).

Also I use a sword and a fire spell. The enemy runs from the fire spell allot of the time so its like an extendo' shield at times.

Kill the enemy faster than he/she/they are trying to kill you. that is how to defend yourself without a shield.

Block that [censored] with your face, like a true Son of Skyrim.

im using light armor and im a hybrid rogue/mage using dual swords and magic

Yeah, me too, except without the dual swords (usually).

My strategy tends to be stay hidden, and if I get seen, rely on either illusion magic to make them flee, run away while laying down runes, or occasionally dual cast destruction magic and heal myself at intervals. Usually works pretty well.