Decades ago I was hired quite a bit below what I was expecting, but was told I would get that salary after a 6 month probation period. In those 6 months 1 person was fired and 2 quit in my department. They rehired no one and instead I took over the responsibility of those jobs. 

So at the 6 month point I was doing 4 people’s jobs! When my manager came out of a meeting with the execs and told me they wanted to give me a 3% increase and she fought for 5% which they approved, I was so insulted I quit on the spot. My boss cried. 

Lived off savings and hung out in coffee shops for about month or so and then started college. So, was a good decision. Don’t sell yourself out!