Water in my oil

I have a 1999 Chevy Blazer 4.3 L v-6 2wd w/166,000 miles. I got it stuck in the mud yesterday and noticed it overheating when I would revup the engine. I got it out of the mudd and when I was driving home it ran hot and shut off. I let it cool and checked the fluids I noticedthe oil looked "milky". I understand this would indicate a blown head gasket or cracked block. It ran fine once it cooled off. I am replacing the oil and filter here in a bit but what else could it be and is it costly?


Thanks for the help
Jesse