Please HELP!!!!!!!!!!!!!!!!!!!!!!!!!!…

You shouldn't be trying to repair water leaks in the loft of yoru rented property - that is definitely the responsibility of the landlord. Water can only come from a few sources - in a loft it has to be either rainwater falling through holes or seeping through walls, or leaking from pipes or tanks. So he is definitely responsible for fixing the original problem. If there was enough water to make the ceiling fall through then there would have been extensive evidence in the loft around the area of the hole - so if its compeltely dry then your original explanation will not be believable. You might as well come clean. But as you say, why was there a floorboard missing, thats negligent and dangerous although possibly your contract might have said you must not access the loft. I think you need to stand your ground and not let them bully you into feeling responsible. But it might be better to say you went up in the loft to FIND OUT what where the water was coming from rather than that you were trying to do a repair job. Water is always a serious issue and it would have been responsible if you were going up to see what was going on in order to alert the landlord.