Have anxiety because I only want one child

I have a beautiful almost 2 year old baby boy and am finding I don't want to have more.

I am worried that he will be lonely. He has lots of cousins and they are all close in age and see each other often. My husband and I are also going to let him be involved in as many activities/sports he chooses and I know when the time comes he can have as many friends over as he wants.

I am just worried but I really don't think i can cope mentally with another baby.

Don't know what response I am looking for but just needed a safe space to write my thoughts. Thanks for listening