I will have to say, I find the infernal mobs highly infuriating. It's bad enough having a bunch of silverfish come at you and practically kill you. Then just once you think you might make it through, an infernal one pops out and smites you down.
I didn't have another weapon handy, and by the time I got another one made, all my items despawned.
On my way back after getting back my hotbar items, I mined some more, then got knocked down by a angry zombie that shoots fireballs! It sneaked up behind me and took me down to 2 hearts in one shot. I was wearing full iron at the time! Edit - It killed me as well as it summoned other zombies to itself and I got mobbed by it and 2 others.
The only tip I got out of all this is to make a backup set of armor and weapons. Swap the weapons out occasionally so you have another set leveled up in case you need it.
The frustration in all this has almost made me quit magic farm entirely and go running back to GT. I was doing so well with my food supply too.