Corsa d , oil on thermostat

[Marksmalls]

Hi I'm losing lots of water and I've got oil on my thermostat,  any ideas please, it's not got much power either, I know it's only a 1.2 but should be more responsive

[Vauxhall Owners Club]

Sounds like head gasket failure if the coolant is mixing with the oil

Would have it checked as soon as possible to avoid damaging the engine