Hi I Don't Know If I Need To See My

Hi I don't know if I need to see my doctor or not. It is so difficult to get an appointment that I haven't bothered. I am getting out of breath a lot, even when I am sat still. I am also very, very tired all the time. I sleep at least 8-9 hours every night and without my alarm I would sleep longer. I am tired all day and if I am home I easily have a 2 hour deep sleep in the afternoon. This does not stop me from being tired and doesn't hinder my evening sleep. I have also put weight on and can not lose it. I am too exhausted to do lots of exercise but I have joined 2 different diet clubs in the last 4 months, followed both plans exactly and lost nothing. I had a week off work last week just to sleep. Most nights I had 12 hours straight sleep and still woke up tired and napped a couple of hours in the afternoon. Don't know if this is a phase or something more serious.