Ive migrated to new host, now I cant save changes! Help please!!

It’s taken me DAYS to migrate my site over to a new host, and after I did a victory dance for seemingly migrating my site successfully – guess what? Nope.
After I tried six ways from sunday to migrate (FTP, database export, etc) I finally did something right and saw my website again! Then realized that only the homepage had moved, none of the links worked. So I reset the permalinks (that was probably the easiest problem I fixed) and they worked again, yay! So when I go back to fixing/tweaking/playing with my small business website – made a couple updates that I had fallen behind on – thats when I realize that everytime I make a change to any of my live pages then hit “preview changes” – NOTHING CHANGES. I tried “updating” still no changes! I don’t understand what’s happened? What did I do wrong and how can I fix this before I go bald officially pulling the last bit of my hair out?!?
Also, apologies if this isnt the right place to post this question but I really don’t know what this problem falls under, and it’s a very BIG PROBLEM. Any and all help is much appreciated, Thanks!!
~Michelle B