One thing that occurs to me when I read your first post is, what does heaven mean to you?
For some it is a hope to hold onto, while things around them are miserable, for others, a reason to be virtuous here and now. It is something that you cannot grab hold of now, and is not what you can aim for on a daily basis.

You also say in your later post that you feel you have to contribute something. While that is a good objective, it might also indicate that you feel you don't deserve to be happy. Are you thinking that things that you would enjoy here and now are not for you for some reason?
Yes, it is great to contribute, but contributions can be non-earth-shattering things. Being a good friend, being there for people in small ways can be a way to contribute to a better society. Isn't that a goal that is worthwhile?
You don't have to find the cure for cancer or pollution or some huge task.
Find some small things you do enjoy dong and do them, regularly, just for you. You cannot be a happy person for others if you are not happy for yourself.

Don't burden yourself with the need to find some huge life objective. One may come to you one day, but you do not have to have one to live a full and satisfying life.

Setting yourself a huge target, living for a dream, can be great, but it can also set us up for disappointment. We are not all astronauts despite many little children dreaming of becoming one. We aren't told as children of the satisfying job of designing the elbow joint for spacesuits that mean astronauts can move around. Or designing meals that are still tasty months later, so astronauts are happy to stay for months in space. Or even working in the factory making the precision bolts and screws and seals that make it safe to be there.
Your dream could be to do well at whatever you do.