Jungling doesn't feel fun

I've been playing jungle since Lux release in S1. I peaked D2 in S4.

Jungling feels horrible right now. It feels like I HAVE to go around and win every one of my lanes ASAP before they feed (which has always been the case), but now I'm lower level than everyone after 5 minutes. If one of the enemy lanes gets ahead they feel ungankable. I feel weak unless I'm 3-0 in early game. If they have a mid that roams in to my jungle they can 1v1 me any time they want. It feels like a lot of things need to fall in to place in my games in order for it to be fun for me (ie. not a one-sided stomp; or it is one but in my favor).

I want to play this game and have the kind of fun I used to have, but it doesn't seem to be there. What am I supposed to be doing that I'm not? It feels like I'm walking on a tight-rope, but if I slip up it takes me 20-30 minutes of waiting before I get to try and have fun again.