It seems like you are having Andro genetic Alopecia
The most reliable treatment available is 4% MINOXIDIL
hair spray,two times a day.One thing to remember here that the obvious results can be seen after regular use for at least three months and also you have to apply it for a year long to see the maximum effects,but if after one year regular application you dont see the results then its not for you.
There is another medication called Finasteride
1mg oral daily,its also requires a long term therapy along with minoxidil spray.
you should also take some good multi vitamins
like Perfectil once a day.You have have to discuss these options with your Dermatologist
so that he can review you regularly throughout the therapy.
Regarding your stomach issue you need to see a gastroenterologist cos i cant comment on that.
i hope you ll find this discussion helpful.