Let yourself feel whatever you feel and observe it. Think about how you would react if you saw a close friend or family member going through that. Most kind people would say something comforting or express some form of compassion.
The most important thing to remember is that there will be lots of good and bad things that happen in life, and holding on/ruminating over the past and obsessing over/fearing the future are probably best avoided.
A little reflection and self compassion is good and healthy, but long term rumination and self loathing is when things can get unhealthy quick. Discerning when one turns into the other is difficult, but do your best and try to be self aware of how you’re feeling as you navigate these truly difficult emotions.
Know that this experience, the emotions and the thoughts caught up in it, are part of what makes you human, and that ultimately, it’s one of many experiences that will add up to who you are and who you’ll eventually become. In every moment, you are, whether consciously or subconsciously, engaging with the world and the circumstances you find yourself in, and becoming who you want/need to be.
Be aware of that, and control what you are capable of controlling about who you want to become. It’s like navigating a river, you’re not completely in control nor out of control. Ultimately all you can do is try your best to get to where you want to go, knowing it won’t be perfect nor will it go exactly to plan, but nevertheless you carry on.