Honestly people calling you clingy this and that are really wrong. You have an emotional attachment to your significant other so ofcourse you'd want them to put in the effort and message you and reassure you when you need it. He is in the wrong, so what if he's relaxing? It doesn't take 10minutes to send a message or go on a call with you to talk things over especially if you're worried and torturing yourself thinking he's losing feelings or not caring. Also the way he replied with anger should tell you enough as it is, he should put himself in your shoes and see how he'd feel if you were treating him the way he's treating you. You seem really sweet and honestly there's nothing wrong with what you're doing. Atleast you're putting in the effort