I wonder if you have looked into a Vitamin B12 deficiency. The reason I bring it up is that a deficiency in B12 can cause severe anxiety and loss of appetite, memory loss, dizziness, and other symptoms. You need stomach acid to absorb B12. You can easily get a deficiency without stomach acid. Prevacid effectively blocks stomach acid. If I may ask, how long were you on it? Is there anything wrong with your intestines, that you know of?
My daughter had a B12 deficiency, and lost her appetite entirely. She also lost half her body weight, not necessarily intentionally. She expereinced severe dizziness. She was so anxious she could not pick up the phone to make calls and could not go to work for fear of falling in the street and being hit by a car. After B12 supplementation (she gets shots every week now), she was able to start a new job answering the telephone! She is not nearly so anxious anymore, and has put on five pounds.
If you don't want to go to a doctor for shots, there is another type of B12 that is easily absorbed under the tongue. It's called methylcobalamin, and it is already broken down into the chemical that your brain uses in processing neurotransmitters, so it readily helps with anxiety. It also prevents buildup of homocysteine, a toxic byproduct of neurotransmission that can lead to heart attack and stroke.
I hope you look into B12, because the benefits are many and the drawbacks are just about nil!