Demon's Souls is a game that isn't purely difficult, it is punishing, but it teaches you. I managed to get the Platinum trophy on that game after about 70 hours of play, the first 5 hours were full of rage, jaw dropping disappointment and moments of asking "Why is this game so loved?" but then after those hours, when I started to be careful, when I started to learn how the game behaved and how to utilize equipment, combos and blocking properly, I started to fall in love with the game.
It's a game that doesn't hold your hand, and you know it, but honestly, it does click eventually, and you'll be having a blast.
I suggest remembering these things:
Losing souls isn't a big deal, it might initially seem like that, but you'll gain so many on the subsequent areas it more than makes up if you do happen to completely lose your previous souls. Also, make sure to use souls for healing items, leveling up and anything else you can, that way even if you do end up losing them completely, it matters even less. Just try and convince yourself it isn't that much of a big deal, and it will make dying seem less infuriating.
A little trick you can use to stop world tendency being a problem is killing yourself in "Body form" while you're in the Nexus. Nothing gets deducted, and you can regain your souls by going to the blood splatter you left without any hassle. You do lose a little bit of your max HP, but it's such a small price to pay without the fear of the game getting harder as you tip toward Black world tendency by dying in areas whilst in your body.
Demon's Souls Wiki. Look it up on Google and take a bit of time to read through the introductions and area strategies. You'll find that place an infinite source of joy and help.
I hope any of that helps, and honesty, try your best to stick with it, it is by far the most rewarding game I have ever played.
