I feel the total opposite! Having children has given me a proper worthwhile job which makes me feel important! I had a job before but I wasn't high flying and it didn't feel 'meaningful'. I could call myself an IT Support Officer but now I can call myself a Mother which is a far more specialised and skilled job if you make a big effort to learn how to do it properly. I learned my IT job in a year, but I still haven't learned to be as good at being a mother as I felt at my old job and my oldest child is 5.
I find I get more social interaction than before. When you are working you can't really talk all the time instead of getting on with your work but if you go to play groups and 'mothers' meetings' and take your kids to play with their friends while you have a coffee with their mother etc you can get loads of talking done! And it is easier to talk when you have kids because you have something to start talking about - each other's kids!
You can still go out with your DH in the evening if you get a babysitter and you appreciate it more because it is more of a treat. We like going out for meals but don't get to go out in the evenings as much, so we go at weekend lunchtimes instead and take the kids with us (not AS relaxing/romantic, but still nice). Because we have refused to give up our meals out we've taken the kids since they were babies and they are so used to it that their behaviour isn't that difficult.
And you can go out without your DH while he babysits and it can be quite good for your relationship to do some socialising separately and then talk to each other after about who said what and funny things that happened etc.
You can go to evening courses as well. I like playing my flute and doing a bit of painting but I just don't tend to bother if I am at home, but if I have a regular evening to go out of the house and do it in a class it focusses me more and I actually do it then.
I worked a couple of days a week for a while (but lost my mind a bit so gave up for a while), but while I was 'sane' that broke up the week and stopped me getting bored. And I think it is good for the children to have a bit of time in nursery to prepare them for school and mix with more kids.
Even if you aren't working I think it is really important to have a break from them so a couple of days in nursery/preschool is good. You can do a bit of your own thing on your own in that time.
Something that helps me is to find things to do on set days of the week so that I don't feel every day is the same and endless boredom. Again this is less boring than doing the same paid job every day although depends on the job I suppose.
I hope I don't sound unsupportive by not feeling the same way but I'm trying to say that maybe there are ways that you could turn the situation to your advantage and think of it in a different way. I think a big problem is that society seems to define people by what paid job they have and how much they earn and what they have got materially and doesn't seem to value motherhood as a highly skilled and important job that it is. I think you should be really proud of what you do as a mother.