2000 BMW 323 Engine Temp gauge

Yesterday (Sunday(, it was very cold here - about 8 degrees (upper midwest). I backed my car out of the garage and started to drive to town to do errands. After a few min, my engine coolant light came on. My engine temp gauge appeared normal. The coolant light went off after about 30 min. I figured I'd be taking my car to the mechanic this morning as they aren't open on Sundays. I noticed my heat not working now (great - new thermostat?) I stopped a friend's house on the way home for about 2 hours. I continued home and noticed that the coolant light was on again. A few min later, I noticed that my engine temp gauge was now on RED and lit up. I was starting to pull over and the SERVICE ENGINE SOON light came on. I called a tow truck and had my car towed. I called my friend and asked if there was any fluid on the driveway where my car had been parked. Her husband said therer was a spot (not huge) and it looked like oil. Related or not, on Saturday, I was shoveling snow in front of my garage door and I noticed a small amount of red liquid, almost blood like. It was only a small streak in the snow where the undercarriage of my car would have driven over the snow.

Any chance this is not huge repair? I had a rebuilt transmission just over 3 yrs ago. I just had my water pump replaced about 2 months ago.

Thanks.