Why is kissing your BF so addictive!!?

Im in a LDR, for 4 years, we have never really done stuff together , we had kissed but this evening was the most intense passionate make out ever !!, a lot of stuff happened but i didnt let him take it all the way and he understood, hes had to go now but im craving for him even more now, i dont get to see him till april. I feel so addicted to him, how can i last untill april. Any tips