The best way to toughen up in the magic is enrolling at Winterhold College & pay for lessons (every time you level up, you can go to the teacher for each of the five branches of magic and pay to level up five time). It's a lot of money, but magic early in the game is worse than useless apart from the firebolt spell when you get it from a book.
I'm going to try starting a game eventually where I use nothing but magic for defence rather than weapons for the challenge of it.
Meanwhile in my current game, I'm having domestic problems with Lydia.
Not that she need worry. Barbas is a flea-bitten pain in the rear & his master's not much better.
At the end of the quest involving those two fannyspangles, I got mixed up immediately in another daedric prince adventure about a werewolf and a stag. Against my better judgement I decided to back the wearwolf Sinding as I'm fed up with daedric princes & princesses. Sinding was grateful, vowed to stay hidden all his days so society would be safe, which considering being a werewolf or a vampire is a good way to have a lynch mob on your tail in Skyrim seemed a good idea.
About a day later walking home to Whiterun after using the local giants & their mammoths for target practice
to my surprise, look who I encountered on the road.
Sinding the werewolf from Falkreath, as a werewolf, & about to pass by a Whiterun guards post.
I waited for a battle to break out.
But even one of the guards passed him by on the road without so much as a drawn sword. Maybe the Companions got a law passed giving werewolves ethnic minority status or a protected species or something. Ulfric will be raging when he finds out, "bloody werewolves, coming into Skyrim, eating our children, taking our jobs!"
It was a nice unexpected postscript to that quest to bump into Sinding again, nice to think of him wandering around Skyrim now happy with nothing that raw meat, a pedicure & a bodywax couldn't put right.