Ds1 is fairly well adjusted I think, but I was a nervous first time mother with him, and so when he cried, I was always 'sympathetic' and would echo in my facial expression and voice how sad he was. With ds2 (and now ds3 at 7 weeks) I'm more inclined to 'jolly them along'. I have strong memories of sitting on the stairs sobbing my eyes out with ds1 crying/screaming in the living room and me not knowing how to comfort him. We got through and I don't think that the effect on him has lasted - though I feel pretty bad about it now. Two months is pretty early for smiles - ds3 has just started smiling, but that means one or two a day only.
I read somewhere recently that it's not the 'high pitched tone of voice' that babies respond so well to - it's any voice where the speaker is smiling. I try to remember that a lot.
I also find (you mention being lonely and isolated) that my babies have loved noise - ds3 now has his best time of the week when we go to a play group for ds2. I've been going for a year, and some weeks I don't talk to anyone very much, but the children love the noise/different toys etc - do try it, even if you have to take a book to help you not feel like you're sat there obviously not talking to anyone. Even better, you might make friends with people in a similar situation...