Yea if there was oil on the dipstick then theres no way in hell it was 5+qts low...unless that tiny drop was from oil running on it from the dipstick tube. Your car would be knocking like hell as well as running extremely hot if it were that low, not to mention that your oil pump would probably be whining really bad from being starved of oil on hills and through fast turns etc. You wouldve had tons of problems already if it was really that low...and thats considering the engine hasnt grenaded itsself yet.
The oil HAS to go somewhere. If it was burning it that fast you would be leaving massive clouds of smoke, and if it was leaking that bad you would be leaving huge puddles. Honestly, you would have to be completely retarded to not notice losing 5qts of oil in 3k miles, and since you managed to get on here and make this post i doubt youre that retarded lol I would have them change it again and then drive it around normally while checking for smoke/leaks once or twice daily. If it is losing oil that quickly you will see it and be able to figure out where its going. Dont trust those lube places, ive had some friends that work there who dont know their ass from a hole in the ground. Good luck man, and i hope it turns out to be something minor.