My girlfriend or boyfriend broke up with me because she said the feeling weren’t how they used to be, what can I do to re-spark her feelings towards me?

I don't think you should be putting the blame on yourself. But talking to them about why they lost those feelings and what you could do is always an option.

You don't have to. ex's are ex's for a reason. If you really love that person you will respect what they want. You don't nesiccarily have to just get over it but try to move on. Try to be okay on your own. the end of the day you can't control other people, you can't depend on other people, but you can control and depend on yourself. If you need to cry then cry, or scream or break something. But don't try and force someone to stay in something they don't want to be in. But remember that the way they feel is not your fault. Everything is going to be okay.