When I like someone I just freeze!?

So basically I'm outgoing but when I like someone and they come up to me I unintentionally make it super obvious that I like them because I don't say anything (or if i do all my words get mixed up), I just turn red and laugh super obnoxious. But with anyone else whose just a friend or someone I don't like I am the most easy going, friendliest person ever. How can I get over this? It's really embarrassing and obvious when I like someone and EVERYONE can tell !