Welcome to Sclero Forums. I'm sorry you are feeling stressed and that your hands are starting to feel tight and look shiny. Other health issues can sometimes mimic scleroderma in the hands, such as diabetes for example, so the best thing to start with is to see your regular family doctor. Get an overall physical exam and also explore ideas for dealing with stress in a healthier manner.
We all go off the rails sometimes in trying to deal with stress inappropriately. I have found that its just not stopping the bad things that help me, so much as starting to do things that might help me more. I am a miserable failure at simply stopping any bad habit, however, I sometimes enjoy a measure of success in simply starting up something even better.
When I'm starting to veer off course, I like to make lists of things that I find enjoyable and relaxing, and then do them. You may have simply not made a long enough list for yourself yet so that you can pick from the best options for the circumstances. You'll know that if your foremost stress relief options do not include things like nature walks, beautiful music, creative projects, candlelight, reading, massage, pets, support groups, and all sorts of hobbies.
Voicing your concerns here is a great way to start, kudos for you! Replacing some of the coffee with a bit of herbal tea might be a pleasant next idea to consider.
The thing is, you are obviously feeling very stressed right now. The thought of changing jobs or quitting anything might make you feel even more stressed, not to mention your health concerns. Unfortunately, stress can worsen nearly any affliction -- although, amazingly, the right sort of stress sometimes bestows benefits, too, particularly if we respond to it with a few more healthy choices.