Ionesmum - I'm SO sorry that I made my comment about you being a bit of a worrier in another thread! I meant it kindly, and to tell you that I am exactly the same.
You sound like you go through all the same worries as me about child raising, and all the same fears about safety for you and your child. You are just a few months behind me. Every post you make, I say 'I went through that too', which is why I often respond to your postings. I hope that my flippant reply did not add to your feelings of self doubt, as I would feel even more thoughtless than I do now.
Everything the others have said is true, and you must go and see your GP. I am lucky that my previous depressions did not return as PND, however, I have felt very near to it at times, as you may see from some of my postings. I totally empathise with you about feeling stuck in the house because of your dd's routine, and needing some time to yourself. I have been there. It is important that you make time to get out of the house as much as possible, even if it is only for a walk in the fresh air. Your dd will not mind having a sleep in her pushchair. Also, meet friends in town etc. Having a coffee in town with friends and/or family is a special treat for me (supplemented by a piece of cake of course!) Your dd will love being out and looking at all the people and lights etc.
Also, could your dh have dd for an evening, so you can have a girly night? I go out with my sister once every 2 or 3 weeks for a meal and a night in the pub singing Karaoke (I know, I know, but it's fun!), and I always come home feeling better and ready to face another day.
My worst moments are because I don't have many friends to see, so I often find myself in town on my own, or walking manically to Tesco, just to get out of the house. It is hard to make yourself do something each day, but I can assure you that your dd will like it, as it will give her something stimulating to look at.
Good luck, and keep us posted on how you are doing. I can't say how sorry I am if I ever came across as a bit hard in other threads - I just wanted to assure you that you were doing everything well, and not to worry. I could have done with knowing about this site when I was at your stage.