Sarah, a turning point for me in therapy was looking at what I'd been through and then having more compassion as a result.
In terms of stressors, you've bought a new house, found there are bigger issues than you thought and you are having to work harder on repairs, you had to suppress who you are and had to move in with your parents, you started having health issues, you had to reveal your diy status before you were ready, your health issues were never really clearly diagnosed so stress is probably contibuting, you lost a close long term relationship, your reno's are taking way longer than expected and are costing more and you are doing this all alone.
Just one or two of these things in isolation would be enough to make anybody overwhelmed and depressed.
It would be great if a few of us could posse up and help you out for a week. But I don't think that's possible.
Please be just a little kinder to yourself.
There is nothing wrong with coming here and venting a bit, even if all we can offer is a bit of compassion.
You do have a bedroom fitted out, so it's not like you are getting nothing done.
A big hug for you and I do admire what you are doing in the circumstance.
My solution would be to ball up and cry.
PS. I forgot you are on a diet as well!