Sounds like it probably is CTS then. A few recommendations:
1. if you are overweight, try to lose some
2. if you smoke, stop
3. try to get some wrist splints to wear at night during a flare up. You will probably have to get these through a doctor (a problem I know if your GP is 5000 miles away)
4. surgery is a last resort but can be effective - if it were me and it was significantly interfering with my life, I might get one hand operated to see what happens and then get the other one done if it helps. Only you know how much this is affecting you
Only other thing I can think of is a condition called vibration white finger. It affects people who regularly use vibrating power tools such as jack hammers. It is a variant of Raynaud's phenomenon where your fingers turn ghostly white in the cold. I doubt this is your problem though.