How do you deal with envy toward your friends?

When it comes to strangers I’m usually fine. I accept that envy is a natural human emotion. But when I feel envious of my close friends I feel terrible about it.

I genuinely love and appreciate them and consciously I want the best for them. But sometimes when they share their successes while I’m going through a difficult time in my life, I feel this unpleasant feeling inside.

I hate feeling this way and I really want to get rid of it.

I’d really appreciate any advice or thoughts.