Hi and welcome to the family al77. A few years ago i was prescribed this and had a few side effects. One being i put on a stone in weight in about a month and like your self, i felt a bit groggy for a few days. I came off them as my G.P felt they were not helping, but there are a few side effects people can get. I would discuss them with your G.P. but please keep on taking them at the prescribed dose as they will settle down in your system.