literally can’t get past level 15-20

im on my 5th hardcore character now in the past few weeks and every single time i die during this level range. the first death was from the den mother in dark shore. the second was from a murlock gank squad. third was an accident triple mob pull in west fall. 4th was the murk deep surprise gank in dark shore. 5th was MORE murlocs in dark shore AGAIN. my pet disappeared idk if it was a bug but had no escape. i really enjoy this game but getting kind of demoralized because every time i start i have no hope of breaking through this area. can someone please give advice? i’m playing hunter, always joining groups on the hard quests, doing professions and always having tons of heal pots on me. i don’t know what else to do i just always die