Hi
It can take a while for reports to come back from your GP. You should ring the GP and make sure they've gotten the forms (often times they may not have), and also explain that you need them back as soon as possible, as your mortgage depends on them. Often these can take a while to get sent back, but if you stay in touch with the GP's secretary it can speed things up a bit.
A lot of people have had medical issues in the past, this does not mean they can't get insurance cover. It may mean you have to pay a bit extra, or try a few companies however.
So don't panic!
Best of luck
Nicola