going to make an appointment with doctor to help with weight gain

but I don't know how to explain what i want and i don't know what will happen when i go to see them.

Does anyone know what will happen and what I should say?

I'm not sure what you're saying. What exactly are you seeing the Dr. for and what do you want out of it?

to give me advice on how to gain weight healthily ect.

Oh I see! Well, it depends on how much you want to gain/why you want to gain/etc. If you ask me, I'd say put on the weight gradually.

Don't worry, if you have a good doc they will make you feel comfortable. They will want to help!!

Are you talking about a gp? Many don't know a lot about weight gain but I still think it is important to go and get a physical. I encourage you to be honest about why you are under and ask if they have a nutritionist and or therapist who you could be refered to.

are you suffering from an eating disorder or is your low weight due to another reason ? try not worry about it , if it helps make a list of things you d like to discuss . the doctor will want to know how you are feeling. he may want to check you physically weigh you and take some bloods . hopefully from there he will deside whats the best step from there .

I have no eating diaorder just find it really hard to put on the weight

What do you mean, "find it really hard to put on the weight"?

Have you always been this weight, or did you lose?

Do you restrict food, or skip meals?

How many cals do you eat?

Are you ill in another way?

I don't really understand...

Since you don't have an eating disorder but find it difficult to gain weight, I think it would  be good to write down what you eat for a couple days.  The most likely reason you find it difficult to gain weight is that you don't eat enough - luckily, that's simple to fix - you'll just have to learn to pick calorie dense foods and eat more often and in bigger quantities.

However, if you write down your daily intake, and the dr looks at it and it turns out that you ARE eating enough, but you aren't gaining or you are losing weight anyway, that might indicate a more serious problem.  For example, it might mean that you have a thyroid problem or a problem with your digestive system. If that's the case, the dr would need to run some tests. So, it would be helpful if you could tell the dr approximately how much you eat on a daily basis.