first of all let me congratulate you for having this feeling bcs many are in the drunken state of life issues. the very existing you now is the greatest proof that you existed previously and have gathered causes to enable you in rebirth. learning truth of rebirth is rejoicing bcs we aasure ourselves that i am going to be there in next birth after i will be dead in this birth. The deathfear is slightly smoothened . But according to buddha , there is rebirth or it is not there also. whole thing depend on you. if you are content in this life and also hope the same shall be in next life also then go on happily. But a little fraction of the futility of life comes to know you though temporarily through any means for e.g love break,cheating partner,loss in career ,deceived by friend or may be due to unknown reasons then the search begins to get rid of causes causing this. then the knowledge begins , what are the causes for getting this life . when learnt ,one strives to avoid them to avoid next birth. buddha's teachings are for this only. i suggest to read "art of living by william harts ,a very convincing analysis of buddha's teachings as taught by goenka guruji who is in lineage of lady sayadaw,sayagyi u ba khin . as per my personal experience i immediately grasped the analysis and feel blessed for developing faith in the teachings of buddha. hoping and heartily wishing to develop the same in you also.bcs we are all diseased and once the diagnosis is done treatment can be done by a neighbourhood chemist also.