My name is ***** ***** I'd be happy to answer your questions today. I'm sorry to hear that this happened.
I'm sorry to say, it's too late to sue your ex-boyfriend now. When this happened, you would have had a claim for defamation of character, and likely IIED
if this was something that happened repeatedly.
The statute of limitations for defamation is unfortunately only one year from the last time he sent a defamatory email or repeated negative, untrue statements about you. Cal. Code Civ. P., Section 340. The statute of limitations on intentional infliction of emotional distress is only two years. Section 335.1.
However, the statute of limitations for trespass is three years from the date of the incident. Cal. Code Civ. P., Section 338. So you could still sue for the entry into your apartment while you were there, in the middle of the night. The judge has total discretion when deciding how much to award. If nothing was physically damaged, they usually give a nominal award (which could be less than $100 - there's just no way to know). The suit would have to be filed in California, though, and you're not allowed to seek the costs of traveling to the trial from your ex-boyfriend. But if you're planning to visit California at some point, you may be able to file a couple of months in advance and request a trial during that time (talk to the clerk of the court before doing that to see).
I apologize that this was probably not the Answer you were hoping to receive. However, it would be unfair to you and unprofessional of me were I to provide you with anything less than truthful and honest information. I hope you understand.