How do u stop jealously?

ok well i am a jealous person and i hate it!!! k well my bff brittany hangs out with this girl names gabby and when she hangs out with gabby she dosent talk to me she just talks to gabby so i am like super jealous and brit dosent have me in her top in myspace and we r like best friends!! omg ughh!! and me and gabby use to be like bff's until brittany moved here and so now her and brit are like sure besties and gabby had me in her top i was her third well now brit is her top friend and on brits gab is her top friend and im not even on gabs top no more omg wat do i do and sryy i am a fast typer so if i misspelled sorry haha :)