Dio, telling someone that you've had enough of watching movie that you've watched repeatedly is not lacking in empathy. Likewise, if you watch a TV series together and become tired of the silly plot, it's OK to say so. It's just being honest. Would she really expect you to continue watching it while bored and not say anything? This is not a personal affront to her and she's silly to get offended by it.
On the other hand, saying to her "If you don't wanna talk to me fine! maybe we should talk less now on" if she takes to long to return your text is very childish of you and can only result in her becoming defensive and having a fight. What about saying "when I don't hear from you, I feel X"?
If these are good examples of the kind of things which upset each of you, I think you both need to learn to chill out. One of the best pieces of advice I can give each of you is "don't sweat the small stuff". In a relationship, it's SO important to let the minor things go. To not get angry about them....to just take a deep breath and let it slide away without comment.
And when one of you does need to comment on the behaviour of the other, it must be done in a way that doesn't involve accusing or attacking them. (your response to the slow texting being a perfect example of how not to do it).
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.