Is it Possible to Politely Cancel a RSVP for a Destination Wedding due to Financial Reasons?

I'm sorry if this isn't the best spot to post this, but looking for some advice!

I have a friend who has already been married, but is doing a small destination ceremony in Hawaii this coming February. When I first heard of this, it was a year in advance, and I was SO very excited!!! When I received the official invite, I texted her saying I was definitely interested in attending and being included in a VRBO together with the group of 17.

It's about 3 months out to the wedding, and my financial situation has changed drastically, where I am now essentially living paycheck to paycheck. Any additional expense requires me to dip into my emergency savings, and just recently I ended up paying about 4k out of pocket for surgery for my cat. I am now being asked for the payment for the VRBO reservation, but it made me really nervous and I'm wondering if it be irresponsible to take another 2k from my emergency fund to afford it. My mom even offered to lend me money, but I don't feel comfortable doing that. My mom needs the money just as much as I do.

I would like to call my friend and explain the situation to her. I care about her dearly and would love nothing more than to celebrate with her in Hawaii, but I'm worried about losing control of my finances and a safety net. Is it possible to politely decline my invite for this reason? I really am worried and don't want to hurt my friend.

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