welcome to the forum
Yes, the symptoms could be due to underlying stress
as you are experiencing them since april when your mother passed away, which is a big stressor in anybody's life (i am really sorry for that).
These could be the symptoms of underlying depression
for which i advise you to consult a psychiatrist
. However, keep in touch with a general physician for symptomatic treatment of your gastric trouble which is also important as you are loosing weight.
Hope it helps