simple observations

happiness (pleasure) has a chemical aspect - endorphins, etc.
thus
happiness is real

you can learn to notice your endorphins when they 'kick in'
thus
you can tell when you are 'happy'

you can note what you are doing/experiencing when your endorphins are active
thus
you can learn what 'makes you happy'

so...
accept that happiness is real
accept that you can tell when you are happy
accept that you can learn to increase your happiness

most important
accept that only you are reponsible for your own happiness