How do you mend a broken heart?

k its wayyy 2 long of a story 2 tell so ill give the shortest version. im female and 18 and been in love twice with other girls. the 1st time it ended really bad. it was an online relationship and i found out the person had been keeping MIVE secrets. it lasted for about a year and i was really crushed afterwards... then i met another girl she seemed perfect. the time we spent together was amazing.. but then things went downhill fast and now things seem like there over b4 they properly begun.. and now im heartbroken again.. i cant stand the hurt feeling and i dont no if i can do this again... it brings back the feeling of the 1st girl aswell.. like double heartache... i now believe that falling in love was the biggest mistake i ever made