I dont freak out easy,but we have a fucking crypt in our house!!!!

Okay,two weeks nakaraan my sister,brothers,the cousins and i went down to the basement to hang out(we usually do this) but this time,somebody started messing around with the walls and opened a secret door.We all went through it and found that there was a passage with a few chambers-which we peeped into.We all agree that we saw what looked like sarcophaguses chiseled out of stone.we slightly opened one but before we looked inside,we all ran away and havent been down there since.
Thing is,i think we may have let out something we shouldnt have.I keep seeing a figure in the corner of my eye but there's nothing when i turn to look.Everybody else who was down there pretends there's nothing weird but you can see them flinch and freak out at the stupidest sound and are restless,so i know im not the only one.we cant switch lights off coz there's fucking something in the shadows.
What should we do? We are all afraid to tell anyone and the parents wont ilipat to a new housf.
sorry for the terrible sentence construction i think there's something in the corner and im scared shitless