The first couple of times in playing Fallout, I never returned to the Vault until after I had the chip, since they had "technical difficulties" in opening the door back up.
Bloody well done at blowing up the mutant base at level 5! Bloody bloody well done!
This wont affect your game in a bad way very much other than one or two quests (optional ones) wont be avalible to you. Now that you have got the water chip and talked to the overseer again you should have discovered that he is worried about the mutant threat and that you have to track down the source and leader of the mutants (or somthing very similar to that).
There is a lot more of the game to go yet, blowing up the millitary base so soon just means you will have a very big boost in experiance early on, nothing major.
Again bloody well done at defeating the base so soon, when I first discovered necropolis I too choose to go talk to the mutant leader, however after a while I quickly realised what a bad idea for my character that was as he was mostly fitted out for combat and basically every fight I got into I got wiped out, I didnt have tycho or Ian with me so battles very quickly ended in me melting into goo.
Damn fine job blowing up the base so soon, it isnt a bug or cheat or anything so dont worry, just means your character got DAAAMN lucky.