i had a very similar experience. approx 3 weeks after my RNY i was hospitalized due to a bleeding ulcer at the anastamosis site. i experienced vomiting and pooping blood too. i was hospitalized for about 4 weeks until the bleeding was controlled and the ulcer began healing. i had a number of endoscopies (camera down the throat) to perform cauterization and so the docs could monitor the situation. i was NPO (no food, only water, fed through IV) the whole time to allow the ulcer to heal.
when i got home i was on a nexium and carafate regimen of 7x/day. i was extremely careful with my diet and basically only ate the blandest of foods for months. in time, it all healed up and now i am functionally normal and have no dietary restrictions (other than the standard RNY recommendations). i still take 1 nexium per day.
it was tough, but its a known and relatively common complication of RNY surgery. i know what you're going through and urge you to hang in their, it gets much better!