Do you think I’ve been fair? Pregnant bridesmaid.

Hi
Cut a long story short. My best friend was my bridesmaid. We’ve had three postponements ( thanks covid!) and have been planning our wedding since 2018!
She has never shown any interest in the wedding, never asked how planning was going or if I needed any help. Was meant to organise hen and didn’t. My sister ended up sorting it. Basically, you wouldn’t know she was even a bridesmaid tbh. Anyway , she’s now pregnant. Totally ok with this and I’m happy for her. However, I’ve already paid £120 for a dress that now doesn’t fit her. Spoken to my seamstress who said she wouldn’t be able to match the fabric ( it’s an odd ball colour) and only option was to purchase another dress for it to be cut up and made into a maternity dress. That was another £120 plus £80 for the alterations. Totalling now for just dresses £320. Now, I do believe that if I ask someone to be in my bridal party and wear a certain outfit , that I pay for it. But I had paid for it and it’s not my fault she decided to start a family . My view is she should have offered to cover the cost of the other dress and alterations. I also asked her if she still felt up to being in the bridal party and I was told she was and she still wanted to do it - fine with me. However, no offer of any financial help at all which I’m a bit hurt by.
Following on from that , I then get a text to say my seamstress has said to her that the dress might not even fit on the wedding day. I was surprised as this wasn’t what I was told. She then offered to just ‘ get her own dress’ after I’d spent all that money . I phoned the seamstress and she told me that was absolutely NOT what was said as it was a complete lie. Now, maybe she just didn’t want to be a part of the bridal party anymore and didn’t know how to tell me but I’m so hurt as I did give her the opportunity to ‘ step down’ BECORE I paid all the money out for the dresses and I made it clear I wouldn’t be offended as I know how hard pregnancy in the third trimester can be ( which is what she’ll be come the wedding) I explained that I’d rather have her there as a ‘ special guest’ if it meant her being comfortable and happy than pushing her to be in a ‘ role’ where she felt too much pressure. I’m so so hurt :-(
I haven’t responded to the text abbot ‘ just getting her own dress’ Do you think I’m being unreasonable being angry and hurt ? Should I still proceed with her being in the bridal party or just take her up on her offer on her purchasing her own dress and she then comes as a guest and not my bridesmaid?
A issue I’m conscious of is her partner is my husband to be best man! I don’t want to rock the boat too much as he lose him but then on the other side I’m angry I’ve been lied to and hurt that my ‘ best friend’ has expected me to fork out for something that want my doing.