Well for one you play amumu and ww both of which are bad. Warwick is bad because he is just bad. Any champion who is only useful for their ult is not a good champ. Since devourer is gone every jungle even some off meta jungles outclass him. After mid game when the top, jungle, adc and the mid(if they are smart) have qss you are 100% useless. Amumu on the other hand is bad because he is a team fight/pick only jungle. He is bad at securing objectives, pushing, he isnt even good in the front line. He is more or less blitzcrank except you have to engage as opposed to pulling someone for a free kill. With him being nothing more than a bandage toss and ult he is heavily team reliant which means if your teams are bad as you say they are then amumu is 100% useless.
Play strong meta jungles if you want to climb. Go to champion.gg and look at the top 10 for jungles and then pick ones that are not team reliant. Go with hecarim, zac, kha'zix, volibear, gragas, sejuani, graves etc. These jungles are not only good for team fights but they are all(for the most part) strong early, easy to snowball lanes with, have strong gank potential which means you can snowball lanes, decent jungle clear and can go tank or damage depending on how fed you get and what your team needs. The rest is all about decision making. If you snowball early then your 1st item should almost always be a damage item to further snowball and then tank after(except on graves/kha obviously). Other than support imo jungle is the hardest role to play in bronze unless you play something that can hard carry.
