Hrobinson,
We may have posted at the same time. Didn't see your post until just now when I was checking in.
First of all WELCOME BACK!!!!

Glad you had a good vacation. Hopefully you are feeling a bit relaxed.
I think you should follow your heart. You don't want any regrets a few years later. If you got the opprtunity to try one more time and you feel strongly about it, then you should go for it. It could work

which is what we all wish for. But even if it didn't, you'll feel better within yourself knowing that you tried your best - it just didn't happen. Sorry - don't mean to be pessimistic, but sometimes we should consider both sides of the situation.
But thats just what I would do. Obviously we all have different points of view and at the end of the end its for you and your DH to decide as only you know ALL your circumstances.
Regarding your clinic not responding, maybe you can just turn up at the clinic? Or write to them? Silly question, but is it possible that the clinic was closed for a bit? Or that the number has changed?

Sorry just realised thats not very helpful.
All the best with your decision. And let us know.