I'm really not sure why I'm so jealous

So I have two kids (I'm so done) and not wanting more. I have a coworker who got married in sept and said she wants to ttc ASAP. She keeps liking things on fb that are baby related so I think she might be pregnant. I'm so green with envy and jealous 😒. I can't come to terms with why...maybe it's the excitement of a first pregnancy again? Maybe. Or maybe subconsciously I miss being pregnant? Maybe an outside view can help me...has anyone experienced this before? How do I get over it? I hate feeling this way...