2005 Pontiac Grand Am Low Coolant and Oil

I got my oil changed around 99,200 miles, and around 101,500 miles my change oil light came on. I didn't really think anything of it until I checked the oil, realize that I lost around 2.5 quarts of oil within 2,000 miles. The light came on 1,000 miles early. I had my boyfriend change the oil and it took him around an hour to get the bolt off from the drain plug. I took my car to a local oil change place and they seemed to be under the influence, smoking marijuana before I pulled in. Anyways, the bolt on the drain plug was put back on by them with an impact. I was told that you should never do that because it's a bad idea. The oil also came pouring out like it was water. Even though the oil in the oil filter came out thicker. I'm not really sure why that had happened either. What I am trying to say is that I'm not sure if my car is burning oil, or I have a blown head gasket. Because my coolant runs low around every 2 weeks also. If it's not a blown head gasket, what would it be? I also sometimes can smell my exhaust inside of my car, and it's a very strong smell and then it goes away.