Thanks for the query
Bleed from the stomach ulcer
often comes out as clots which can look like dead skin, as you have already been diagnosed with gastric ulcer I dont think further investigation is necessary for the bloody stools.
Please continue taking the medication prescribed for it. I would like to add here that bleed from the gastric ulcer can show up in the stools upto 5 days.
Also I suggest
1. Do not eat spicy food, milk and milk products
2. Abstain from alcohol and smoking
3. Have meals at regular time intervals, eating smaller meals several times a day is ideal instead one large meals thrice a day
4. Avoid bending exercises
5. Do not sleep immediately after dinner
I hope I was of help