Where do I go from here with my life, and “our” future?
It is so hard when you feel like you were pursued and then the other person decides that he/she is not ready for the relationship or that the relationship is not what was expected. It sounds like the old adage "It isn't you---it's me." might be appropriate here. There are two of you that have to determine what is "best" in this situation. One possibility would be to keep the lines of communication open and try to maintain a friendship. It sounds like you are very important to one another, so maybe that would be a good stepping stone back into the relationship at some point.
It seems important that you share how you feel with him and see if he is willing to answer some questions or discuss in depth what "not the right head space means". It is noted that he used the word "yet" when talking about the relationship. For many, it would be important to have more details so that you can have a better understanding of what is going on. For example, if it is a not yet situation, would you be willing to wait until he is in a better head space?
Finally, my advice would be to really look at your own feelings. He seemed to really want the relationship and it grew serious quickly. You have met his friends and family, which allows you an opportunity to create relationships that stem from your relationship with him (so the breakup creates more than one loss for you). Truly think about if you miss your relationship with your boyfriend or is it the loss of other things including being desired. It is natural to want to be pursued and desired and when that is gone it can be painful. Finally, if he is struggling in life, you would need to determine if you have the time, energy, and effort to either help him or just simply wait for him.
As you know, relationships can be very hard. Sometimes, the relationship is absolutely worth fighting for and sometimes it is better just to let things go. The difficult part of your decision is that you have to decide what is best for you but you cannot make the decision for him.
Be patient and take care of you!