These skills make a defense check. It happens to everyone using this kind of build, especially when fighting Duriel since he is in a small room. Later, it won’t be as painful when you have easier access to physical resistance and higher HP. Since you have low hp, you get hit repeatedly and faster hit recovery kicks in, slowing your escape. Changing gear for higher defense would lower your damage. If kill speed is good, stick with what you have.
For now, try to aim for the shaman in the halls of pain first, he is the one exploding the corpses. For Duriel, simply stand next to a tp. Admitting you invested a bit in faster hit recovery, when situation goes bad for minions/merc or you see too many towers, go back town. Both builds you mentioned have their guide in the guide section. Perhaps your gear is not optimized.
As for mana issues, your problem is most likely going to solve itself by aiming at high energy rolls on charms. Worse case scenario, respec to remove excess strength and dexterity. Charms really help on this.
As far as I know, Dream Eater steals hp based on a fixed percentage of damage dealt. No stat can increase this. Someone might correct me on this.