How Do I Clear Mucus From My Throat?

Hello, i just got the common flue few days ago and I ve just got my heat back to 37 °c, however i woke up right now in the middle of the night caughing and then this slimy thing jumped up my throat, I guess it was mucus... But it wont get out, i tried three times to caugh it up, but when it got to it s highest point I felt like puking and had hard time breathing, so I drank a lot of water and found it sinking a bit down my throat again. My question is, will it be allright to go back to sleep and just let it sort out naturally or do I have to do something about it? Please respond I m having hard time over this!