Easy bruising, fatigue, muscle pain and nausea are symptoms of Scurvy, which might be caused by lack of stomach acid. Lack of stomach acid causes many nutrient deficiencies. It is treated by taking cheap over-the-counter Betaine (hydrochloric acid). Scurvy itself is treated with vitamin C, of course, but betaine deficiency is more likely to be the underlying cause. This would also explain the tummy trouble.
I would call into Dr. Bob Marshall's Healthline radio show. The show is recorded Monday thru Saturday, and he answers questions like this. He often recommends betaine because deficiency is common.
Dr. Bob Marshall’s staff answers health and nutrition questions on Saturdays from 10 AM to 7 PM (800-370-3447). If you want to talk to the main guy, you probably have to call into the radio show.
Lots of diseases cause these symptoms, so it really does no good to treat for what you are not sure you have. You only mask the real health issue.
I had to be off all my vit/mins for 2 weeks for a simple platelet test.
Full blood work up is needed. Each one to rule out, each of a dozen different diseases it could be.