Feeling like this is very normal in the first few weeks. I felt very emotional and teary and for me it passed. If it doesn't pass then go and see your GP.
In regards to your inlaws - massive hugs! If I were in your shoes I would be on the verge of something too. If people are there then they're there to help, not be entertained.
Start delegating. Your time is taken with bonding, resting, feeding, sleeping, caring for your baby. If they can't respect this or your wishes then time for your DH to have a quiet word with them.
People forget that it's not about them and their wishes or wants. They need to be reminded. I've found this became a lot easier for me when I became a parent.