"Must have" is actually a number of things as the threshold for a diagnosis (ie. not one "for sure" symptom). I started writing a response when you first posted, but didn't finish (sorry!). The gist of it was about the curious mix of hypersexuality and depression. I wondered if it was a self-esteem thing as opposed to depression per se. Is this a possibility? When one's self-esteem is very bad, it's not unusual to look for outside validation, and it's also not all that unusual for it to be in the form of sex. But of course that feeling of validation doesn't last long and then another is sought, a pattern which can get rather out of hand. Don't know if there's anything there -- might be a stretch. It'd definitely be worth talking to a professional -- especially as it bothers you so much.

Your English is very good, btw.