I feel like I've destroyed all my friendships with one mistake

Hey everyone, so I really messed up. Last week my now ex ended a 1yr relationship saying that we both need to work on ourselves. Saying they still love me but if we stayed in a romantic relationship everything would fall apart. We went out to drink and have a sesh, they were all over me the entire night especially when no one else was around. We both had some alcohol, them more so then me. We both went to sleep in the back of a friend's car. I tried my hardest not to give into temptation but I eventually caved and we both had sex. I feel like I took advantage of them cause they were drunk, I tried to beg for forgiveness but now they're not talking to me and none of our friends are either. I know what I did was wrong, I just don't want to be left alone again.