Hook up guilt

So I’m a 23 yr old single girl and I hooked up with someone two nights ago (purely casual) and I feel so much guilt! This has happened before too where I hook up w men randomly (not often) and then get guilty although I enjoyed it when it was happening. Like this time - I did everything except sex and I woke up anxious, my throat felt slightly sore and I feel like I made a huge mistake. Someone assure me that casual hook ups in your 20s is completely fine and fun...right?