Should you be happy with your life? How can you tell if you're happy with your life? Well, would you be willing to go back some number of years, say to when you're in childhood, or teenage years, or in your 20s, or whatever, to start over? If you are willing to start over not just for the thrill of doing something new, but to "fix" something that you honestly believe can be fixed, then perhaps your current life path isn't optimal (this is almost a tautology).
If on the other hand you dread going back and having a redo so you could lose whatever it is you have right now, then you're pretty happy with your life I'd argue (regardless of what it is).