There are many definitions of happiness. For some it is a great bottle of wine at the end of the day. For others it is the satisfaction of helping out at a soup kitchen. It is different things to different people at different times.
The question really should be, what does “happiness” mean to you?
If you can’t answer this question then how will you know if you are happy? Or whether you could be happier?
The trick is to find an answer that is meaningful to you and then to work out how to get there. And then to actually get there. It might take work, and it might mean changes from how you live right now. It will be worth it.