How to feel content in your career?

Dude in my mid 20s. I work in the physical commodities industry, with 3 - 5 years experience. I take home a great salary + bonus, and work very decent hours (albeit, my phone is always on). 

So great pay, good hours. There are other reasons why I am maybe justified to feel pissed off, but I'm still doing really well for my age. 

Yet, I find myself constantly frustrated. I have hit a bit of a plateau. I would say I've reached a point in my career where it's more about relationships than skills, which isn't a surprise. But these relationships take a lot longer to build than learning most skills.  

I feel like I deserve more responsibilities, more credit, better opportunities, etc 

Also, I find myself feeling jealous of others who are becoming super successful, and feeling they may be less deserving (whether true or not). And I would say it's more down to my personal competitiveness than anything about money. 

So how do you always stay positive, and lift up others?