well my boys werent that close - 3 & 6 and the last couple of years have made me feel horrendous. Its not fun and question who much enjoyment is in having young children in the home while your left to juggle housework, chores etc while the OH can escape back to the adult world.
Actually, this isnt uncommon, speaking to 'real' women who arent scared to open up also say they spent the first few years in constant tears.
If there is PND or general depression (unsure if there were issues before the birth of DD1) its understandable. Seems to be lack of discussion on how real mums feel when left at home. What you feel is what many feel dont feel hopeless.
I found keeping a strict routine worked for me. That way I could feel control, knowing why baby was crying, knowing what I had to do next to keep on top of everything. What doesnt help is lack of sleep this can seriously stir up any depression or feeling low. Again I found with a routine (book style) helped but the poor sleep sleep with head chaos makes a cocktail of unable to cope.
I found once baby in routine going outside was more manageable. Could you think of joining the leisure centre and some have creche facilites. Get some exercise and freedom without the pressure of joining in with other people. I'm sure getting a bit of exercise may give you a little buzz. Agree about groups far too many women talking about repetative 'natural' birthing and 'how I wouldnt change a thing' (while I puke!).
I cried loads after a terrible birth with DS2, no one helped me, no one understood that I failed to give birth naturally again. I do think having a breakdown histerical moment is pretty common not just women who have depression suffer.
Being at home with two young children cannot be underestimated I'm glad you can talk about it.
If you can, see about some cognative therapy, it helps loads, you may have to pay but its worth it.