Cant manage the unmanageable

How can you ever be sure your doing the right thing at the right time? I’m sitting here trying to study everything all at once, because I live a life with nothing but stress. I’m filled with regret cause no matter what I do it doesn’t seem to be enough or the right thing at the right time. I’m reading one book while I probably should be reading the other books. My weekends disappear to obligations to which my heart is split on the decision making. How will I ever know if I'm doing the right thing at the right time? Making mistakes is horrific and it leaves behind stress and debrief that I really can’t take right now. Lost lost lost
I feel bad. Sometime more the others I wish things would go back to when I had time to focus to do what I wanted to and what I needed to. Living in this present with obligations that are not my own is a burden. Not everything has gotten better with time I tell you. I’m finding myself in a constant guilt trip, gosh even taking a shower takes more time out of my day then I have to spear. No matter what I do I still feel as if it’s not helping me forward, just stressing me out right now and destroying things for later on.
How can I manage two jobs and two classes all while balancing life's musts and needs? I haven't found myself doing anything for me in a long time, gosh painting my nails is the only me time I'm able to give out and it’s only every other week.   I’m stressed, guilty bound, and can I say (well at this moment) less happy. Finding a minute to read my email (god forbid to answer an email) or to send a massage to a friend or a loved one is not something to which time allows.