Who's still depressed from Thanksgiving?

I had to go home and see my family for the day on Thanksgiving, and doing so brought me down pretty badly. I realized that I'm actually jealous of my little sister for being engaged to be married before me. Being the oldest, I always thought I'd be the first to move out, first to graduate from college, first to get married, etc. I love my sis, and her fiance is a great guy, but I just felt hostile the entire day and haven't been able to shake the feeling life is passing me by since then. THEN that brought back thoughts of the ex-girlfriend, and it was all downhill from there. Ugh. And to think, Xmas is only 19 days away too. It's gonna be a long month.

Let alone be married? Pressure from expectations of the family?

If you're under the age of 50, rejoice in your freedom. Life has much to offer you, and marriage isn't a prerequisite.

I watched my own children and had a sister. I guess it is normal.

you are realizing you want more out of life than you currently have.
I was divorced 10 years ago, the thought of my ex can still upset me on occasion. The best thing you can do is really try to let that go. There is someone much better out there for you and the ex relationship may have been wonderful at the time, but just not meant to last forever. Or maybe it sould have been forever, but something tragic happened, something really wrong took place, someone or something toxic interfered. In either case you can not change history and can not be happy until you let it go. How you do that I have no idea.