In light of life's obnoxious tendency to throw millions of curve balls at us at once, you can temporarily strikeout, and ignore the stigma against having a pity party, one in which you are the guest of honor.
Like a boomerang, life can suddenly propel us out into the unknown due to events out of our control. But there's strength in feeling sadness, as long as you find your way back, like a boomerang.
It's OK to feel sad from a bad grade
First, embrace the disappointment. Sounds counterintuitive, but remember how painful it was to be surrounded by a bunch of Gretchen Weiners, getting asked the inevitable: "So what'd you get???" and having a different response from the majority of the big-haired know-it-alls. Let the tears come out like a monsoon, while simultaneously experiencing a hurricane of emotions, surging between guilt, sadness, and denial. You then have to tell your parents about this personal, natural disaster of yours. But where there's pain, there's room for gains. Analyze what went wrong, vowing to yourself to never feel this way again. Did you miss the class that had essential lecture material? Is taking notes on your laptop too distracting? What are your preparation techniques? Are you merely passively reading a textbook or actively studying flashcards? Use your failure as motivation, because it can only go up from here.
It's OK to feel hurt from rejection
It hurts to feel like second best, it hurts to be an unintentional participant in a disappearing act, and it especially hurts to not know why, instinctively leading to internal attributions for our failing romantic lives. You're allowed to feel sad over your relationship that never was, because this seems to happen every time you allow yourself to become vulnerable to someone else. Feel sorry for yourself because it's not you, it's him (99.9% of the time). Listen to some old Tay Swift, write a poem, eat some chocolate, but don't build up that wall: the wall that'll eventually take an army of men to break down. Maybe that .01% was your lack of supportive communication. Reevaluate what went wrong (or who it went wrong with) and see where the room for improvement is. Where there is rejection, there is resilience.
It's OK to some days feel like a whale out of water
We're not supposed to feel 110% every day. Bad body image days are part of being human, unless you're Regina George or Kristina Riccitello (love ya, sis), it'd be concerning if you sometimes didn't feel like the circumference of your hips is comparable to that of an airplane runway. Do not force the "positive self-talk" when you genuinely feel crappy about yourself, because the good days are already guaranteed to come with the bad, and it's perfectly fine to feel imperfect. However, when you realize these feelings are persistent and the "bloatedness" is here to stay, then maybe you need to make adjustments to your daily routine, possibly by incorporating a healthy exercise regime into your routine. What does your diet look like? If the body dissatisfaction is prolonged and dampens your mood on the daily, it's time to change for a better you.
Sadness is the time we develop proper coping mechanisms against life's unpredictable curveballs. Sometimes, it's necessary to temporarily strikeout, because this is when we acquire our strength for the next inning.
You can even be fashionably late to your pity party... just don't overstay your welcome.