kuraiza - Something that's helped me to get out of the house is to get everything ready the night before, while DH is around to help look after DD.

I always make sure her stroller is ready to go, so that after a feed and change I can put her straight in her stroller and leave the house.

Also on some walks I take my ipod with me and listen to music - it makes me feel like I'm just walking around and not looking after a baby IYKWIM. I get to disconnect from things mentally a bit, I get some exercise (which helps my mood) and often she'll fall asleep for a little while if I walk far enough.

I hope things improve for you soon!