My third son was stillborn at 31 weeks. After his birth by c-section, I still had some mild pregnancy like symptoms. It's normal! things will eventually return to their normal state. If not, see your ob about it. God bless!
It takes some time for your levels to go back to normal. The breast tenderness will go away with time. I miscarried Sept 29th and it took awhile for things to get back to normal. You still have hormones left over so that could be pary of your emotions not to mention that you just had miscarriage so that could be part of why you feel down. I wouldn't worry about it. I am sure you are going to be fine. Just give it some time.