Do you have much support at home from your partner? Support in the early weeks is really important... it's so easy to feel overwhelmed and you need someone to be able to prop you up a bit. If you really feel you're not coping you might need to have a chat to your gp, but in my opinion it's still so early that maybe you need a bit more time for things to settle into a routine yet.
You're doing a great job hun, don't doubt yourself. xx