Forgive yourself. There will be times where you will stumble and regret past decisions but come to peace with those decisions. You are not those decisions. You are the person who has learned from those decisions — and if you process them correctly, you can achieve anything you want. There were months where I wasn’t sleeping due to decisions I’ve made in the past, constant rumination, and day after day I was self inflicting myself with mindless inner chatter. Learn to silence that voice. You are not the person who threw up in your friend’s car, you are the person who has learned from that experience. Accept it, and move forward.
Try to see yourself in others. Imagine someone stole money out of your purse or intentionally keyed your car — what would be your natural reaction? I would guess your instinct would be to call this person a mother****** and have a burning desire to retaliate. That would be natural human response. Now, if you can take a deep breath and say to yourself, “have I ever been in a situation where I would of done something like that?” Maybe you could, maybe you couldn’t. If you can’t see yourself doing something like that at any point in your life, then look at your family or close friends, perhaps they would have done something like that when they were down in the dumps — in need of a couple bucks for a quick high.
It’s not easy to look at things this way, it’s honestly quite impractical. However, if you choose to see yourself as the person who wronged you, your outlook on the situation dramatically brightens. Personally, I’ve made so many mistakes and done things mentioned above that it makes me sick even thinking about it. However, the past is the past and the only thing the past does is limit your present moment. So, flush it. Flush whatever happened and make peace with that person who wronged you. Negative things will only come from a negatively charged, emotional response. Of course your initial response will be negative if something bad happens but it is paramount that you take a step back, take a deep breath and let it go.