You may hate this answer.
I'm a few years older than you and about to get my math degree so I can't offer you
career advice as I often look for that myself. I have, however, been through the ringer
so to speak and I identify with so much that you are saying.
Stop taking your life so seriously. Stop desperately trying to define what your brand of
happiness looks like with so much detail. If you somehow develop the perfect path for
your life with everything laid out meticulously then you are setting yourself up for
tremendous heartbreak because your life doesn't give a shit about what you plan for it.
Be a good person, take small but thorough steps to overcome your laziness, and try to
accept happiness that comes to you. Never turn down happiness because it doesn't look
like what you planned. You don't want to become so overwhelmed with fear of the
future that you don't recognize true happiness in a different form.
If you don't go to grad school then you still have value. Life in our society is mostly
about selling yourself – hard. Maybe you can't win a Fields Medal or whatever, but if
you can't sell your background to *someone* then you're just a bad salesman, not a
And please understand that I'm dishing out this advice while striving hard to follow it