Nether entire mechanism having issues

I went to nether last time to get some xp at fortress.But when i use a arrow from distance, the arrow floats on air for 5 second and the arrow fell on ground instead hitting the mob.As the arrow  floats in mid air the mobs r able to dodge it..And also when i stack up with block, the blocks get disappear and fell and i almost died.And sometimes the mob takes time to get damage after hit and vice versa.I am really Afraid to go to nether in order to prevent lose my inventory and xp.this is my issues on minecraft.