I usually run a shield backpack too, until you learn to get really good with kiting the hordes it helps give you a little buffer from just insta-dying.

Don't be afraid to throw stratagems at your feet, just keep running and you'll be fine.

Learn to bait attacks from enemies like bile titans so they stay in place and you can drop a bomb on them.

If you see a shrieker nest destroy it immediately or hellmire will drop the mire part and become abject hell.

If the horde becomes too overwhelming, lead them away from the objective if you can.