This is the philosophy that lead to my name. If you base your happiness on achieving goals or avoiding suffering, you'll likely find happiness fleeting. You can look at people who most would consider great examples of success and still find miserable people and suicides. My guess for some of them is they get there, are happy for a time, and then when it eventually fades as they get used to their new position in life, they either think there's nothing more they can chase or that something must be wrong with them if they can't be happy and start feeling even more miserable because they have the problem of not being happy.

Happiness isn't a reward for achieving a goal, it's a decision we make about what we feel about our current circumstances. If you're not happy, you can change that by adjusting your circumstances or by adjusting your expectations. Both of those are worthwhile pursuits, though IMO the second one is more important because it will allow you to be happy on the way and after you've made the changes you'd like in your life.