CHEATING?! heLP

so I know I'm going to get a lot of shit for this but trust me I feel absolutely terrible, like sick to my stomach. my boyfriend is overseas for a month but we've been in contact every day ( were both only 18) and tonight my friend came over and as a joke (as you do at sleepovers) we went on omegle, I told my boyfriend and he was fine with it. but we said we were just joking around, about ten minutes ago some guy was jerking off and asked us to take off our tops, and we did it?!?!? I feel so extremely bad like did I cheat on him? how bAd is this from an outside perspective? I feel awful please help