Hopefully not insulting your intelligence, but wanted to share my experiences at your point of "stuckness".
First char I made was kinda like this, but as I knew more about the game and adjusted a bit, now my 2nd and third chars fair much better in Hell. There is def a hurdle once you get there though. Bosses in particular become a game of a cat and mouse for some builds. Don't be afraid to back off, but Andy in particular likes to drop meteors so .... you have to dance with her. I'm not even afraid to jump in a portal anymore and just regen and blow potions, but I know with my melee sorc, I had the tendency to kinda try to let my leech do a bit more than my kit could handle and would get rolled a lot until...
Main thing that helped me on my chars was making sure I was hitting resists as high as possible even if I needed to shove perfect gems in what I thought were spots I needed to save for later and making sure I tried to work on my most important breakpoints. Hopefully you did your level challenges and got your class gems and pumped them up too. Nothing you are wearing in the first set of gear is going to be permanant and there's nothing that's completly irreplaceable, but you'll have to invest and dump your gems/runes into your kit and make sure you are following the advice on Mystic Orbs.. I overlooked all this stuff because in D2LOD you could /kinda/ wing it then you'd trade for a few pieces and be a monster, but this game has a slower buildup until you learn the ropes. Even if 5% str doesn't sound like a lot, do it anyway. You can easily flush gems out of TU's with a few gold, so don't be shy about cramming them full of anything and everything.
Also some classes/builds and guides in particular are usually written by people that have played it a bit to death. Look over the breakpoints and playstyle a bit and actually see if you can make it better for what you are shooting for. I did this with my throwsin and it actually made a difference. The guide (it was outdated to be fair) recommended a bunch of heavy armor, but I found light armor to give me more damage so while I'm a bit more glass cannon, it works much better than trying to turtle up with defense.
Also want to second self-healing. Wormtouge belt and crafting jewels that use Ber rune (for more leech) has been my jam for melee chars.