It is hard to deliver a remote diagnosis here.
However, all airliners that I am aware of have multiple independent hydraulic systems taking their liquid from dedicated reservoirs, driven by at least two pumps each. On A320 series aircraft, there are three systems in total. Should one of those systems fail, it will still leave the aircraft flyable and only result in some additional considerations and extended checklist work: all the really important systems are taken over by the two remaining systems, other systems have a backup operating mode not requiring hydraulic pressure. For example the landing gear can be extended via gravity extension if needed. If a second system goes, the aircraft will still fly, but there will be various systems offline. One hydraulic system is required to be operating on nearly all types in order to keep flight controls powered. Exceptions include the F70/100 and the DH8-300, those two types still allow the use of the primary flight controls without any hydraulic pressure available. On the Dash, you will only lose the rudder and the flaps.
There are various protections and additional systems included to make the loss of all 3 hydraulic systems extremely improbable, ranging from using different power sources for individual systems to routing the pressure pipes well separated from each other.
However: on the ground, things look different. While the aircraft may be flyable when the system goes in flight, there is normally no reason to depart an airport without having presented such an issue to maintenance and having it rectified. Depending on the exact time the problem rears its head, it may well even be illegal.