Why I'm happy for someone..but seeing their happiness makes me angry..sad..and upset?

Maybe it's because they used me as their own personal punching back...is it jealousy of not having what they have?...is it that I'm jealous that they got to em first?

I've never felt this way before I don't want to feel this way

I don't want to feel "jealous"

I don't want to hate them for seeing them happy