OP, I felt the same after having DD, I had to stay at home for 9 months on mat leave and hated it.
I had no money (was paid SMP which went straight into paying bills), I had no friends in the area at all, and just felt like I had lost my life and sense of identity. DH could still work, see his friends, earn money (even if it was for the both of us, I wasn't happy at not being able to contribute myself).
So I don't think you are being unreasonable at all, it is a very normal feeling under such circumstances.
What helped me was to get out each day, even if it was a walk to the shops, and also joining lots of baby groups, then being brave enough to ask mums over for coffee afterwards.
I don't know whether this is feasible where you live - do you have any groups nearby? Or just somewhere you can sit on a warm day and read/drink coffee whilst baby sleeps? It all helps.
If you can chat to DH and let him know how you are feeling - maybe he can take over with baby one weekend and you can get out and about a bit?
It does get easier as baby gets bigger and more responsive, and as you begin to find your feet.
I have since had baby number 2 and have quit my job because I love being at home with them both this time around.
HTH