too much stress and irritation...

Am really not sure if you have tried this already but if I were in your place, I would just stop resisting such a mil. If you have to live with her, and there is no way to fight back and win, just withdraw and let her have it her way. Don't keep harping on the animosity you have for her in your heart because that will just make things worse for you. Reduce every chance that can lead to friction with her. Dont badmouth her with your husband or anyone else for that matter; you will start feeling better about yourself. Try and work towards this and think that you are doing yourself a favor. It's her time now- let her win.

There will be a day when your time will come too. Try to look out for a job; you seem to be well educated and will surely find a fine job. This will not just give you financial independence and respect in your husband's eyes but also will divert your mind from your mil and your baby that you so tragically lost. When you are mentally and physically ready, try for your baby again and I really wish you will then have all those things you are now longing for.