How to deal with overwhelming guilt
 

Basically the past week or so I've been wracked with terrible guilt.
Before you say it- it's not a symptom of my depression, it's a legitimate and warranted, deep guilt.

I've done a lot of shitty things in my life, I've done terrible things to lovely people.

I feel so guilty it makes me panic inside, I feel sick and I just want to break down and cry. It actually feels like the start of a panic attack that doesn't come, maybe because I don't let it.
I don't know why the guilt has come now, but it's so overwhelming.

How can I deal with this guilt? I can't take it!
I feel like I should confess one thing I've done to this someone, but it'll inevitably cause me so much pain because it'll probably make this person leave me. I guess I deserve it, I shouldn't have done what I did. I'm kicking myself for it.

I don't know what to do.
Please help. :-(

Make peace with yourself, it is not easy and it doesn't always work but tell yourself these things are done and gone. You won't always listen, it won't always work but sometimes it might.

You say it is not mental health related but I do wonder how your mental health is at the moment. It is just that I find that when things aren't so great, my mind pulls on everything I feel ashamed of or guilt about. So although the thoughts may not be mental health related but that is not to say that it is not exacerbated these thoughts.

What you would be advising a friend in this situation?

Could you write out an apology or explanation to the people you feel you have wronged? It might help to get it out.

I understand how you fell. I have done shitty things too in my past and it haunts me sometimes.

I agree with what tiptoes said about imagining what you'd say to a friend if they told you they had done what you have. Can you find the compassion to forgive them or even to understand? Ultimately, we do what we do for a reason.

I also find it helpful to accept what I have done and learn from them. It makes me want to be a better person. If you are genuinely remorseful and learn from your mistakes, are you really that bad a person?

Nobody is perfect. Everybody has done things they regret and wish they could change. People aren't all bad or all good, everybody has bits of both.

Lastly, I would advise you to talk to someone you trust about these things. Their reaction may surprise you.

Take care.

Thank you both for your thoughtful replies.
I've been writing some of my thoughts down which helps a lot.
My mood has been low at times lately, so I guess that does add to it, but I just feel that I'm generally not a nice person at all and the things I've done are horrible. I've been selfish, I've hurt people I care about. I'm not nice and I don't want to be me.