So apparently i was at that point in the game where you have to choose a Faction... Only i didn't know it!! I found the Railroad and wanted to team up with THEM.. but before that i decided to go to the Institute cause i was eager to find Shaun first ... after going there and doing one of their missions i finally got back to the Railroad only to find the main lady saying they can't trust me anymore.. Now problem is i only have like 5 game saves-3 of them are too late in the game where i still can't join them and the other two are where i just get out of the Vault - WHICH BASICALLY MEANS START OVER FROM SCRATCH-

So i decided to go on with the game and kind of unwillingly joined the brotherhood, the plot has been interesting but my hearts just not in it.. ): i saved Danse in thought that maybe its kinda like siding with the Railroad (plus at the Bunker Hill mission i set all of the synths free) i tried joining the them again and still nothing..AND THEN i get the mission to kill all the railroad leaders???

So my question is- is there some kind of way where i can join the railroad without starting over? some monologue choices i can make to switch sides even after doing that one stupid mission? or at least some way to not kill the leaders? PLEASE HELP I'M SO BUMMED OUT BY THIS