While you didn't have all the details, what I could gather was simply that this dream could have been attempt to end or finish (kill) some sort of situation that was eating away at you. In trying to hide all the evidence but ending up swimming in water indicates quite possibly that you are the evidence and there's an attempt to cleanse yourself of what ever this thing is.
Could be something as simple as some type of error made in communicating with someone that you feel bad about. Or it could speak volumes may be a work related situation or major relationship has gotten you pretty angry--so you are trying to kill it.
A suggestion would be instead of trying to fix the problem, perhaps you should do some introspection. You may be surprised to see the solution is not as drastic as you think.
Anyway, that's just my take on it--dreams are always up for speculation:)
Regarding the rest of your inquiry--I have many dreams about flying, and it feels real--the cold wind in my face.
Sometimes dreams are simply dreams. Other times, a dream is a vision with a message. You will generally know this because it will have such a profound impact on you when you awaken, you'll remember every detail. At these times, you will feel like you were awake. And in truth, you are in that special, special place--the spot before you awake but you aren't sleeping..I actually enjoy those moments. That's where the truth lies!