Speedometer stopped working all of a sudden

Two problems. 1. Last night it was -10 degrees outside and in the morning I went to start my truck for work, I turned it on and let it sit for a few minutes like I always do to warm up but it had this loud scretching sound coming from what I think under the hood on the drivers side. As well as once I started driving the speedometer stopped working, I was going approximately 25-30 mph and my speedometer shot up from zero to 120. And stayed there while I drove the faster I went the louder the noise got and the speedomterer was pushing to break. Also my heat stopped working about 2 months ago, it worked fine then all of a sudden one day it didn't want to heat up anymore. It turns on and blows out air but it just doesn't get hot. Its not ice cold but it doesn't get hot at all. As well as my air conditioner works properly if that has anything to do with anything. Please help! And I am a female and don't know much of anything about cars so please respond in detail. Thank you!