Furnace cylcing very quickly and sounds..."funny"...?

A few days ago when I was in the basement, my furnace kicked on and I thought to myself "huh, sounds different..." but I tend to be the type to notice everything and find problems that do not exist. I just wrote it off. This morning, as I was lying awake in bed, I realized I had not heard the furnace kick on for about half an hour. I thought this was great since it is getting a little warmer out...hopefully we are nearing the end of the cold season. Then, to my dismay, I heard it kick on. It ran for about 5 minutes, blew hot air, and shut off. No problem. Then, about 10 minutes later, it ran again but only for about 3 minutes, and shut off. Immediately after shutting off, I heard the thing kick on again but shut off after literally 3 to 5 seconds (never actually blowing any air this time.) The stupid thing then kicks on AGAIN after only a few more minutes, runs for about 2 minute