Engine Cooling problem
2002 Vauxhall Astra Front Wheel Drive Manual 125000 miles

hiya, iv got a 1.6 sxi astra. For the past few weeks its been using alot of water but its not going into the oil? In my water bottle there is a little drop of white sludge floating about. Is that a sign that my head gasket is about to go or does the engine just need flushed out as it had a new radiator 5 months ago? The temperature guage has strated to get slightly higher when driving. Thanks!