If you are reading this then most probably you were happy and now you are not, and you are trying and trying, to get back there. The happy you, but it's just not working.
You have 2 options:
option 1: find a way to feel better all the time. Keep doing it, not find a way to feel happy, but instead find a way to feel better, and keep doing it.
Eventually in your day if you focus on feeling better, you will reach a state of happiness and you keep doing this every day, then your brain will make it a habit for you to be focused on feeling good, eventually leading you to be happy.
The second option is you have to release the unhappy past memories that are making you sad. Something may have happened, and that's why you can not get to happy level. Maybe it was traumatic, or had strong negative emotion, so it's tough.
It's like a car with it's hand brakes on and you are pr4essing the gas button. the wheels spin, but the car does not move. If you release the negative emotions, then it's like you have lifted the hand brake down, and the car will move.
It's just like that.
We know how strong a hand brake is. Our negative emotions of what has happened can also be very strong or it could be many things that are negative that make it strong, so we have to find a way to release it.