You can get through this. I also have PTSD and have a bunch of strategies and techniques to cope with my particular set of problems, without knowing your particular problems it would be silly to suggest any strategies here. I will, however, start by saying that your reactions and feelings are both unique and common. Anyone would be affected by having your circumstances happening to them. A lot of people feel guilt too, usually over not feeling 'perfect' or not being able to cope and I suspect you already know that it "isn't your fault" and "you are not to blame" but that won't stop you feeling those negative thoughts, that's what humans do. Basically you have to find your strategies to overcome, or at least control, these outbreaks of negative feelings/thoughts. Trial and error comes into it, you have to find what makes you feel good in your head.
For immediate relief breathing exercises are a pretty safe bet, deep slow breathing helps to slow any panic attacks and gives you something to focus on other than your trauma and whatever post trauma behaviours/thoughts you have. It is a long term process and you are now aware that things can come up at any time, mostly when you are not ready for it nor expecting it, that means you have to find your set of techniques and strategies that work for you. Trust me, there IS something or things that WILL work for you, finding them and practicing them is the hard part.
One thing I have found that PTSD sufferers are very good at is standing outside themselves and 'watching' how you are reacting or behaving and then asking "Why ?" of themselves. Knowing your triggers can also be a great help. We all know in hindsight that something we did was maybe a bit silly or a reaction we had wasn't 'needed' but that doesn't help at the time. If you can 'step outside yourself' it helps to catch those things right at the time. Having tools you can use 'at the time' is something we all need to get, to develop and they are different for everybody because we are all individuals.
You may notice I am not even bothered with the past event, what caused it all, what I am upset about, what I am interested in is how I react, what I do, now, here in the present, do I have the tools to control my mental behaviour, to calm myself down to the point where I can look at the present and make my mind run more smoothly. That's the key. If any of this sounded ok and maybe a 'bit' helpful, feel free to discuss anything you want with me at any time.