Is it worse than THIS:


These pics were taken of my Omega V6 oil neck, and at this time of year, it is completely normal. This was particularly sludgy in the oil filler neck because of the castrol oil I was using.
Please answer this one Q - is there mayonnaise on your dipstick? If yes, then it's a potential HG failure, if no, then you're probably in luck, just keep a close eye. You will help reduce it (if it's not HG) by cleaning out the breather system to reduce crankcase pressure (about £3 for carb cleaner!) - and also do an oil and filter change.
Coolant leak is probably Heater Bypass Valve - seperate issue. Have a look and feel around the HBV 1) with engine running, don't burn your hand 2) just after engine has been stopped .. and see if there's any wet. Or any signs of coolant spraying around at the back of the engine.
Is it missfiring? Please don't panic, there's no reason straight away to believe it's fatal.