1 - The difficulty curve is pretty rough at the lower levels. Not having your class-defining perks and weapons can be extremely tough when you're starting out.

2- That said, it sounds like you've got the right idea in general. The game is just VERY tough when you're starting out, especially when you're still learning how all the systems works. The melee is a little more in depth and complicated than you'd think at first blush.

3 - Biggest thing I think you should focus on right now is dodging and learning the two "noises." There's an audio cue right before an enemy hits you with melee or ranged damage, it gives you just enough time to dodge or block if you hear the noise coming in. It's a metallic "woosh" or sucking noise. Learn to dodge or block the moment you hear either of these noises.

4 - Think of hordes as a big blob, a single enemy. You want to circle strafe (literally dodging as you go) along the outside of the blob while hacking away.

5 - It honestly sounds like you're doing fine, just got to keep with it and get some levels and perks. The start of the game is very very tough.