Hello bright. I am sorry you are in this position now, it must be incredibly difficult for you.
I hope the legal process has been explained to you - the 6 weeks wait before you can sign anything and what happens next? I also so hope you are being supported by people around you at this time.
I would say that adoption is not something to plough ahead with if you have doubts. If you don't have doubts, that's fine, but because adoption is so final, it's infinitely better to wait and go slower than have regrets later. If you do change your mind - then that's absolutely fine. You have absolutely very right to parent your own son, so don't feel guilty if you do realise that parenting is the right road for you. We adoptive parents (or me certainly) would want to be sure that adoption was the right thing for our children, and be sure that their birth mother/family definitely couldn't keep them. We wouldn't want to be seperating a mother and child if there was another way.
I don't know how long it will take to find him a family, but small babies are usually easy to place. If he is a healthy boy, I am sure they will find someone pretty quickly. If he has any disabilities or health issues, it may take longer though. It will take a little while after they ar found for him to move in with them, so it will be a few months before he leaves his foster family.
The social workers will be looking firstly at adoptive families their council has approved to adopt, so it is very likely that your baby will be placed with a family who either live in your county, or, if your county is a small one, in a neighbouring county to you. If a child is easy to place, they are usually found a home in their area of the country.
I think writing him a letter is a really good idea, and giving him keepsakes. He might find them very helpful when he is older, as many adopted children have quesions about their early lives and why they were adopted. And I, as an adoptive mum, I really really appreciate my kids having things from their early lives, even just photographs. That part of their lives will always exist, and it doesn't feel quite right to me when you have nothing to show that it ever happened.
No one can guaruntee that your son won't have feelings of being abandonned at some. I'm not trying to be harsh, just fully answer your questions. Children go through all sorts of emotions when they are growing up and thinking about their adoption, and it's normal to have harder times with it. But having things like keepsakes, or letterbox, that might help a lot as he grows even older, with him feeling like you wanted the best for him and that's why you made the decisions you did.
Letterbox, if you are able to do it, then although it is hard emotionally, I personally think it's a good idea and might be very helpful to your son - you can answer any of his questions, and keeping the family updated on what's going on in your life (including any important medical information as it comes up) might also be very helpful to your son later on.
We also can't make guaruntees about what his adoptive parents will be like or that they will be amazing - I can only guaruntee that they will be human! With their good points and flaws like any other human, and they may go through difficult times like most of us do at points. But I can say that nearly every adoptive family I've ever met or spoken to, personally or online, we absolutely adore and cherish our children, and we try our very best for our kids, to parent right and be what they need.
Again, I so hope you are being supported, and many to you. I wish you and your little boy all the best