Hello all, iv'e had a problem recently with a character i'm running. He is a lvl 6 Wizard and is very impulsive. My party and DM are usually good about keeping him out of trouble (But the DM might let me run off just to stir up some action sometimes.) However, during combat were I have more control over the movement of my character, I have him run off a lot once we have kill most of the enemies. Twice now, Iv'e been jumped and surrounded by goblins that all flank me and I go down really fast. Me and the rest of the party like the impulsiveness of my Wizard, and he can add his own thing sometimes, but constantly getting KO'ed subtracts from the game play. Any tips on how I could still be impulsive and not get KO'ed so much? I always have Mage Armor on, but a AC of 13 does nothing when all five goblins have advantage and you only have 25 health.

Misty Step and defensive spells like Shield will let you escape. 

Invisibility. They can't hit you (as easily) if they can't see you.

Thunderwave is great for getting a pack of enemies off of you. 

Expeditious Retreat can get you out of trouble quickly. 

If you weren't already level 6, there's certainly other options for making a sturdier wizard, but you've already passed that threshold. I play a Mountain Dwarf War Wizard, for example, and I have an AC of 19 (+2 Breastplate, +2 Dex bonus, +1 Cloak of Protection), with an additional +2 AC as a reaction in a pinch. 

Thunder step looks pretty good for you.  You can run into the middle of the enemies; tank with mage armor, shield, and maybe mirror image and/or blur; and then get out and blow them up.  Also, lower HP means the cleric's healing spells go further (if you have good enough defenses to make up for it). 

Also, Wiener

The combination of spells I would recommend if you don't want to die to literally everything is Shield/Mage armor (I personally think Shield is more reliable), Misty step, or other teleportation options for running away. False life is nice, if you're in a close combat situation and you need to be able to take some damage. And lastly, Thunderwave is a nice get the hell away from me button.

Checking the defensive spells of my lev 4 wizard:

absorb elements, shield, silvery barbs, gift of alacrity (through fey touched --to be higher in initiative to make my moves first), mirror image, blur, misty step (fey touched).

You can look into kinetic jaunt but I haven't tried it.

Actually, my stars druid was surrounded by drow (and separated from the party) last week and he misty stepped and then dashed the hell away (he was at 1/2 HP).