Rozied,
One day at a time gets easier in time. I still take it 5 mins at a time some days. Your sons are old enough to take care of themselves so let them. They need to grow up and not take mom for granted anymore.
Take a vacation and enjoy yourself and let them worry about life. You deserve to do what you want, you worked and took care of them long enough. I know easier said than done.
Remember you are not helping them only hurting them in the long run. Keep up the faith and work on you.
Hugs coming to you