Hi there @LittleBoxOfHeartbreak. Welcome to ReachOut!
I think that it's great that you and Adam have become close and even more super that you had the courage to confess your feelings! From what you have said, it doesn't seem like Adam hates you, hate is a very strong emotion which I don't think he is showing because he clearly likes spending time with you as friends and joking. The fact that he said he is "honoured" to be your crush shows in itself that he doesn't hate you. There could be a chance that he likes you back if you both make jokes about it and are subtly flirting as you say 🙂
I can see why you're worried and confused that Adam would be flirting with you and hanging out with other girls at the same time.. Ash seems like a good friend as he is looking out for you by telling you things.. but just from my own experience, I don't think you have zero chance with Adam even if Ash thinks so. Adam never said anything himself about his intentions with the other girls and he hasn't told Ash that he doesn't want to be with you. Why do you think that Ash reckons Adam is having possible romantic intentions with the other girls?
Perhaps just give it some time. Time for Adam to work out what his feelings truly are towards you. And after a while if he is still hanging around with the other girls it wouldn't be wrong of you to just ask him about them, you two seem close so I don't think he would be offended that you asked.
Good luck with it all!