ive had a metatrsal fracture, but it was a stress fracture....an over-use, chronic injury, rahter than an acute one.
You can go c a doc to have it officially diagnosed.
Course of action depends on which metarsal you broke. (if its broken)
If its the second one, or the base of the fifth, then you will probably need a cast. If not, then you are merely supposed to "stay off" of it and let it heal. Metarsals generally heal very rapidly. IT will help to ice for the first few days, weeks.....
Id go c a doctor though, for sure, becuas i am definitley NOT one