My (28M) gf (26F) is having a mental breakdown because her friend is getting married

My girlfriend (26f) and I (28m) have been together for over a year. I have a 4 year old daughter from a previous girlfriend. Gf and daughter get a long very well, gf just quit her job and moved in with me full time.

Everything is going great! Until, her best friend announced she just bought a house, is getting married and now is pregnant as well. They started dating about 1 month before us.

My girlfriend LOST it. She has been crying for literally 24 hours non stop. Picking fights with me, just generally acting psycho and having panic attack after panic attack....

I planned on marrying her when I finish college and get a good career so I can afford a beautiful ring and proper wedding. But her throwing a tantrum like this makes me have second thoughts about marrying her at all. We cannot afford a 2nd child right now.

Any advice on how to make things go back to normal?

TL;DR: Girlfriend is putting me through the wringer because her best friend is pregnant and engaged

Update: To clarify some things... My girlfriend pays for groceries, toys, diapers and whatever else she can manage to pitch in on. She WANTS a job. I told her it would be better for her to go to school rather than waste time at some crummy fast food job. I don't want rent from her, I don't need it.. she helps enough with driving my daughter and cleaning up after her it ho estly makes it work, since I have more time to earn money. She is currently enrolled in classes, they start next month. I've started college this year, and am focused on finishing as fast as I can.

I've spoken to her about why she's so jealous of her friend. It seems she feels overwhelmed being a mother figure to my daughter with no silver lining of a child of our own any time in the near future.

Now that her bestfriend friend is having a baby, she has no child free person to turn to for a kid free break. I can see how that would stress her out. This friend has kind of been her escape when she needs to decompress around another adult.

She's incredibly happy for her friend, I don't think she's trying to outdo her or anything. She's not materialistic at all. She is VERY sentimental though.

We share the house work and childcare equally! I do my best to help her if I see she's stressing out.

Yesterday i sat her down and showed her the ring i had picked out for her.... admant that she doesn't want the ring. It would cost me 3 mortgage payments, which I can't afford until I finish school and get a good job. She doesn't want to wait for my idea of a perfect wedding.

I guess I have been a little dense and only considering the proposal I always dreamed about.

She's been an amazing girlfriend and parent. Maybe I have some things I need to reevaluate.

I didn't consider that maybe her pressure is much greater than mine.. I wanted to take my time and have my second kid the "right" way, but she's right.. the timeline I have set up for us means she will have her first around mind 30s, while she's surrounded by children.