Stressing over my sisters wedding.

My sister is getting married in 2 months and I need to purchase a plane ticket since she’s a couple thousand miles away. It’s $500 for just me. My son has to come as well because he’s in the wedding. He’s under 2 so I may not buy a seat for him. The problem is I still have to buy her a wedding gift, buy my shoes, I have the dress already, I have to rent my sons tux, shoes, then there’s hair and makeup she wants me to pay for and do. I don’t mind hair but I truly don’t like makeup. I want to only wear mascara but I get it it’s her wedding so I will end up spending a lot on makeup as well. It’s just going to be a lot of money. I didn’t expect to have to spend $3000 moving for the army. They didn’t reimburse us bc my husband didn’t do the paperwork correctly. So that was a big dent on our savings. We have $1300 in savings but I really hate having to spend it on my sisters wedding. I sound so selfish. Our family hasn’t gone on a real vacation in years. We make money just fine but when stuff comes up we struggle a little. I will obviously be there for my sister but she’s giving me hell over it. She wanted me to shell out 150 for 300 beats for my 10 year old cousin that doesn’t need beats. That’s so expensive for a child. So I said no and then it started an argument. Mind you I paid her 100 to go on her bachelorette cruise and I ended up saying I wasn’t gonna go bc she wanted me to help pay 100 partial for peoples alcohol that I wasn’t gonna drink. So I said no and backed out. This was a deposit. She never paid it back to me. She didn’t even buy the tickets for the cruise yet. So I found that was fucked up but I didn’t bother asking for it back. I just hate how everything is about money with her. I even paid her $40 to help with alcohol for her bridal shower. I’ve been helping her and yet she judges me because we live off of one income. Idk what to do anymore and I don’t even want to attend her wedding. She also told me the other day she expects a speech from me and I have never done a speech before and I’m a terrible public speaker. I’m losing my mind here. I’m hoping my appendix ruptures like a day before I’m supposed to leave. Is that wrong of me?