How can I figure out what will bring me happiness in life?

So I'd like to just reiterate what you wrote... "I've been unhappy," and "I'm not satisfied with what sorta things were happening in the relationship."  I understand all of this was likely negatively accentuated since you guys were living with his Mother, but these were your words that I feel you should sit with for a bit.  It sounds like now that you are home with your Mother, you are noticing other mental health challenges you are having. 

I don't really believe that any -"thing," "person," or "experience" - truly anything outside of ourselves is going to bring us a sustaining happiness or peace.  We may get a quick dopamine kick when we initially get that boyfriend, new car, promotion etc.  but over time we realize we have communication challenges with the boyfriend, a higher car payment with a new car, and new responsibilities with a promotion.  Nothing external will provide us with what we need for happiness.  We have to feel good about ourselves on the inside.  I think this is a perfect time in your life to figure out what is going on inside you...time to unpack what happened in the relationship and time for therapy.  Focusing on you right now sounds like the best place to be right now.  

If the relationship is meant to be, you guys will find your way back to each other, but no need to do that now if you are not in a good place with yourself first.  You will likely not find happiness in others if you are not happy with yourself.  Heart break is hard, very hard.  But being in a relationship that continues to go downhill is even harder.  I hope you are able to use this time to truly focus on your own needs and work towards healing and finding balance/peace in being you.  Fall in love with you right now.. and treat yourself kindly.  It may be a time of self discovery.  It may also be a time that you reflect on what works for you in a relationship and what doesn't.  But sometimes you need to get away from the relationship for awhile in order to figure these things out.  Time does heal, but I know it's hard work, and patience is a virtue.