Can Mononucleosis Be Tested Immediately After An Unprotected Sex?

Hello. i made a stupid mistake today. I went to a massage place. got myself a handjob. Also for some reason i made out with her too. Later when i got home it just hit me how i could have contracted mononucleosis. I m really worried about this. I m wondering how quickly i can get tested and if i get tested early will that help anything?