This 'blowing up her phone' business.....are we talking about you being needy at the time? If so, it may well have been a huge red flag to her. Though only she knows the real reason.
My suggestion is that you back away from her. This will be a win/win for you: a) it may make her miss you and decide that she wants you as a boyfriend after all. b) if she doesn't change her mind, it will give you the space you need to recover from your feelings for her.
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.