Possible head gasket need help

[Leea8]

Hi there I have a 2.8 sport a8
2000 year
Couple off months ago was slowly loading water didn't think much off it as was minimal
Anyway this week started get hot quick going up to 3/4 Mark on temp gauge fan kicks in then goes back to half way
So was use water more and checked header cap mayonnaise around inside and in oil filler cap
Checked again Friday after work and now water is like chocolate milkshake
Is this head gasket as its no over heated
If so I can do head gaskets but would this mean getting heads skimmed and could there be possible piston ring damage
The car has done 140000 miles
I can get a engine complete with 62000 miles would it be easier to just do engine change