1996 Chevy Blazer 4.3L engine overheating

I have a 96 blazer with appx. 155,000 miles on it. The engine recently started overheating really bad, I couldn't drive it for more than 10 minutes before it would actually shut off because it was too hot. I took out the thermostat and tried running it then and it overheated still although not quite as fast. I checked the oil and it was a milky brown color and was way too full. However it is not blowing any smoke out of the tailpipes. When I take off the radiator cap after running it and letting it cool down, the inside of the radiator looks relatively dry. I just had the water pump replaced a few months ago and there is no coolant leaking from anywhere under the vehicle. I am afraid it could be the head gasket or a cracked block but I can't even drive it far enough to get it to the mechanic much less have the money to fix something like that right now. So any help would be greatly appreciated because if I can fix it myself I will but I don't really know what to look at at this point. Thanks.