I have struggled a lot in climbing through silver in season 7 as well. I am a little confused as looking at your account shows you haven't been gold since season 4 but... maybe you have more than one account. Only reason I bring it up is if you truly been gold before then you probably view the game a little different than your consistent silver teammates.
I main jungle as well. This season is unfortunate in farming jungle and out scaling the enemy is not as reliable as it was last season. Jungle was basically nerfed with jungle changes compared to season 6 and experience works a little different. Good news is jungle is still quite strong (has most control over the game) and most likely is still the most influential role.
The main thing with climbing is sticking to a role and certain champions. I would find two or so jungle champions you really enjoy playing (who seem strong in current meta) and spam them. Learn the strongest builds and adjust your play based on your games. I picked up starting to play
this season as I knew he was strong and I had never really gotten into playing him. I struggled for a few games but eventually got better with him and was able to get on a hot streak and climb out of silver. Currently have a 69% win rate with him after 39 games.
Remember silver is still silver and players are basically the same as they were in prior seasons. This season is a little more snowball than season 6 and it does seem like teams start grouping earlier than they used to. That threw me off for awhile but now that I am used to it climbing is not a problem.
Remember as jungle you have control over objectives. Try and control drakes/rift herald. Depending on the jungler you play the easier it is to solo these. When playing
it takes longer and is harder to solo these objectives so I usually focus more on ganking and counter ganking and waiting for my team to help. I have started to play a lot more
and have had some success in silver soloing these objectives when I know enemy is not around. It's really easy to solo these objectives with
.
Get rid of any ego you may have and just focus on each game at hand. Some games will be unwinnable but one thing that has strayed true for years is silver/bronze players are terrible at ending games (so are golds but not quite as bad). Remember each game there is a high chance of the enemy team throwing so try and look at the bigger picture. Just because your team behind does not mean you are out of it. After 20 mins silver games turn into a huge cluster fuck. So if you are a legit gold or higher macro player focus on trying to survive early game and then out rotating/out playing enemy in mid/late game (if behind early). But if you have a strong early lead then try and focus on snowball and closing the game out.