HI, welcome,
Sorry for your problem but the very first thing we need is the model year, model and floorplan of your RV. We can't provide a lot of help without that info.
Next, we're going to need you to explain how you "lost your fluid?"
Also when jacks are down fluid leaves the tank and goes to jacks. Once jacks are back up then you check the fluid. If you fill reservoir now when you retract the jacks it will be over full
Without knowing your RV make/model... if they are HWH hydraulic jacks, the fluid/pump only runs to extend the jacks. The springs on the jacks themselves are what retracts them. Just "store" the jacks as normal and they should retract, if they are HWH. As others have said, need a lot more info here...