So sorry to hear about your loss, bibby. The emotional rollercoaster is brutal.
I'm 42 as well, and similar to you, started ttc very late (had DS at 39). I've since then had 4 miscarriages and am increasingly panicking about the fact that time is not on my side.
I've had my AMH checked, and as expected, my ovarian reserve is low. And two of my four mcs were due to chromosomal abnormalities, which I don't have to tell you are the greatest risk factor at our age.
However, I had a long and thorough chat with my consultant after my last mc, and he was actually very positive and encouraging, stating that I still have a very good chance of having a successful pregnancy. So yes, the risk for trisomies at our age is around 1:42, but if you calculate this 'the other way round', this translates into a 97.7% chance that everything will be fine - which is actually pretty good, if you think about it.
There are so many positive stories around about women with healthy and happy pregnancies in their forties, it is very common! Now I am not the best example for this, but I'm still hopeful that it will happen for me!
Give yourself some time to recover from your mc and look after yourself, you have been through the mill 
As belle has said, it is not an easy ride to take, and only you can decide if you want to take it. Ask you GP if you might be able to get some of the tests done (progesterone levels, for example), (s)he might be understanding and cooperative. But don't be put out if they don't, unfortunately, unless you've had recurring mcs, they will not do anything (unless you go private).
It is not impossible, and you are not alone!
Come and join us on the 40+ ttc thread, where you will find lots of support and handholding, should you decide to try again.