I have issues...seriously

Ever since the cost have houses has gotten low and the interest rates have gone so low Zac and I thought we would try to play the market and get into our end all house.  About a year ago we signed on a house to build but I started freaking out and we backed out of it.  Here we are a year later, we signed to build yet another house with the same builder and guess what....I had total anxiety, depression and panic attacks since the moment we signed.  This has gone on for a week and I have been in a very dark and sad place.  My whole life I have struggled with change...whether it was getting a new pet, going to school, getting married, having kids etc.  It was always a really emotionally difficult thing for me to handle.  I researched a little and found it is an actual thing called adjustment disorder.  Probably hereditary ( thank you biological parents!)  Anyways, we found this house and it is beautiful.  It was in the area we wanted, near friends, schools, had a huge back yard, community pool, a huge laundry room, open office and playroom/game room to grow into, amazing closets.....everything.  It is a very large house and I was feeling so guilty.  From the moment we signed the stress of it all sent me into panic mode.  My heart was constantly racing ( I was at a dr. appointment and my heart rate was 106...normal is 80), I was dry heaving every morning, I couldn't eat and I was always crying. I could not even function and do my normal day to day things...there was nothing there.  I have been simply miserable.  My husband has been amazing and talks with me every night and listens to me sob and repeat the same things over and over.  Somehow moving to this house projected onto other things like my kids growing up, a big house distancing our family and all these other crazy and irrational thoughts that I could not escape.  Zac is so sweet and instantly said he wanted to get out that I was much more important than some house.  I told him I felt so bad taking away his dream and he told me he was already living his dream.  When Ellie saw me crying she would get very concerned and upset. During one of my many many crying spells my Noah came up to me and asked "Are you crying again!?" It broke my heart, my kids need a mom that can function.  I feel so weak that I can not beat this.  I wanted to work it out but truly felt hopeless and sad.e  I knew I could not go on feeling this way for the whole nine months it takes to build.  Zac finally convinced me that it is not worth it at all.  With Noah heading to kindergarten and going through fertility treatment it is just too much.  It takes nine months to build I was so worried about adjusting to a new baby and a new home.  I had concerns that maybe we won't have any more kids and then I would feel really guilty in this big house.  Now I am worried we will get pregnant with multiples and then really be all on top of each other...but we will have to figure that out if/when it happens.  Having backed out of the house I do not feel better.  I feel terrible, like I have taken this blessing away from my kids. I am broken hearted and hate that I have to deal with this. It really feels like it will not pass and I am so alone.  I know that I just need to focus on my family, teaching correct principles and growing in the gospel but with this darkness I feel such a spiritual void. I long to feel happy again and only hope that with this stresser gone I will be able to get back there more quickly.