You might be five months pregnant, but you have not been to the doctor's yet? Yikes. You need to get in there quick. You're supposed to be seeing an ob-gyn during your entire pregnancy. If you are five months along now, you're already more than halfway through it. Is the 21st the very earliest that you could get in there?
We can't tell you if you are pregnant. A fluttering and cramping feeling could mean anything. It could mean pregnancy, it could mean you're stressed, it could mean you have a stomach bug. Those symptoms are just far too vague for us to say whether you are or not. You can never rely on symptoms when wondering whether or not you are pregnant. However, at five months along, you should be starting to show, and pregnancy tests should be showing up as positive for you by now if you are pregnant. I would suggest avoiding alcohol, tobacco, and all of the other stuff that pregnant women should avoid just in case though.