first of all, relax and don't worry
As per your description, you are experiencing depressive symptoms which may be the continuation of grief reaction and for that u need some antidepressants/antianxiety drugs as well as psychotherapy
So i advise you to consult a psychiatrist
soon and your problem will be easily solved
Your weight gain or blood pressure problem may be linked to depression
or there could be some other medical etiology too. So you should also consult a general physician.