Anxiety/stress & Feeling Sick, But Why?

Background:
About a year ago I was going through a relatively stressful time (though not that stressful) and afterwards began to feel sick to my stomach every day, and I mean really really sick though I never actually was sick. I couldn’t eat much due to this and lost quite a lot of weight. I would also have diarrhoea every day and suffered insomnia. I went to the doctors about a million times and had just about every test under the sun, including blood tests and an endoscopy. They didn’t really find anything to speak of that was causing me to feel so sick all the time, but there was excess acid irritating the lining of my stomach so I was put on omeprazole to help this. They also thought that it was stress causing me to feel so ill all the time so I was put on amitriptyline too, which I’m still taking along with the omeprazole.
Ok so basically i’ve been taking amitriptyline and omeprazole for about a year, during which time my symptoms have come and gone. I would have thought they’d arise when I felt most stressed, as I was in my final year of university and under a lot of pressure, just moved house, been on holiday etc – though strangely I felt pretty much fine during this time. Now that I’ve finished university my symptoms seem to have started up again for seemingly. My stomach is feeling very acidic which makes me feel really sick, which is usually helped if i drink something milky or eat a slice of bread. I very much don’t want to spend this summer as I spent the last (ie feeling ill and missing the fun).
Is it possible that I feel subconciously stressed or something, or in some way the fact that I have nothing to do isn’t making me relax, but instead stressing me out? I can’t think of any other explanation unless the whole thing isn’t related to stress at all but totally random.. I’d appreciate any advice or suggestions, because i’m so annoyed at the whole situation!
Many thanks