Ejstrut I am so sorry for this situation, which must be incredibly painful.
Please get some help and advice (maybe some adoption related counselling) before making your final decision if you have any doubts at all.
I cannot offer any advice as I have never been in your position but I would like to give my thoughts as an adoptive mum to a son not relinquished and as a birth mum to a daughter. Both my children are the light of my life and I believe giving up a child is a very, very hard thing to do.
Will the disappointment in your father's eyes be because you are not keeping the baby? I know in some countries and communities having a baby if you are not married would be something that could also cause problems and I am not sure if this is playing any part in your thoughts. (Which I do not personally think it should at all in this day and age but not all communities feel this way!)
If I can give an opinion, which you are totally free to disagree with.... Whatever feelings your family will have about your pregnancy or your thoughts on what to do, you must make a decision for yourself. Even the idea that you will help a couple who would love to have a baby, although that is very noble, should not play into your decision. Personally, I feel that even your boyfriend's feelings should not rule the situation.
In the future you and your boyfriend may go your separate ways and you must know in your heart that whatever you do, you do it totally for the right reasons for you and your child not because of any pressure from others (please do not take offence - it is easy for one partner to lead another along a path when both of you are young and maybe scared).
Do you really want to give up this child? If you are very sure of yourself then I think you may be able to access some guidance on how to talk about this and what to expect from one of the adoption related charities such as BAAF (British Association for Adoption and Fostering)
www.baaf.org.uk/info/pregnant
Thinking of you at this very, very difficult time.