1995 Chevy Silverado coolant leak and white and black smoke

I just recently bought my 95' Chevy Silverado with a v8 a little over 2 weeks ago, and a few days ago after just driving for about 5 minutes well I was doing more idling than driving but when I got to a stop sign the truck stalled out and I noticed white and black smoke blowing out of the exhaust the truck started again with no problems but it was still blowing out smoke, I pulled over on the side of the road after a few feet since I was blowing so much that it was engulfing the truck, I turned the truck off which it acted like it has stalled out again because it didnt turn right off after I turned the key it made a noise as if it has stalled out again, well I let it sit a couple minutes and then I started it back up so I could get home which was only a couple of blocks away. It was still blowing smoke but it was getting less and less until it was back to normal. When I got to the house I let it sit for like 30 minutes to an hour and we started it back up. It blew a little smoke but then cleared up after. We drove it again just to go get our mail and it didnt blow smoke but after a few minutes it started again but then cleared up again after a few minutes. We have not drove it again yet because we do not want to cause more damage to whatever is going on, We had noticed the truck was leaking anti-freeze and we cant figure out from where and we looked to see if oil might be mixing with the anitfreeze but the anti-freeze looked and smelled normal. Some people have thought it might be the head gasket and others do not know. Also the smoke has an antifreeze smell and there is no smoke coming from under the hood. If it may be the head gasket what would be the chances that the head is cracked or warped? Ya the previous owner was driving the truck with no antifreeze in the resevoir. Just wondering what you thought it might be.