Can someone help I just don't feel motivated anymore.?

is it ok to feel sad after...?So me and my friends were at the mall. Me Reed Sarah and Emily. Me and Emily were sitting next to each other on a couch and Sarah texted me "Do you like Emily?" I reolied yes. So later I was takking to Emily and asked if she liked me and she does... as a brother turns out she likes my friend and now my friends dating her. :/ :| :( Like I just don't want to move on I was up until 5 am remembering evetything that was fun and happy between us. :|