Afraid, I'm w/Grace on this one. If they say you are yelling, maybe try to change the way you ask for help. A softer tone or if you've asked 3/4 times and it doesn't get done, leave it. Do not do it yourself. You see, you've always been the strong one and the person who has done everything for everyone else, even during the crisis. It's time now to step back and allow your family to see that you are the one that needs help.
If you find yourself bubbling up and ready to raise your voice or lose your temper over something, walk away, take a walk outside or go into another room and beat the crap out of a pillow.
I know you've had a lot on your plate for a very long time and you are just plain tired. The holidays aren't helping you either. It sounds like you may need to seek the assistance of a counselor or a grief counselor at best. We are here for you, but we are not counselor and can only offer up what we think is best. A professional may suggest putting you on ADs or upping your current medication. It's time to seek him/her out for assistance. Your health is number one now. Focus on your health....it's very important.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.