Painful memories can take over your life, at times feeling as though they are invading every experience. There are a number of strategies which are useful in helping to contain and set these memories and emotions aside, making them a bit more manageable. This does not imply that you suppress the memories or deny their existence, it is an acknowledgement that they are there and will be dealt with when opportune.
You can use your imagination to create containers in which you put your uncomfortable emotions. You visualise yourself doing this. Any visualisation which helps you control your emotions helps. Avoid violent visualisations of where you act out your aggression or anger.
A technique taught in mindfulness meditation is helpful. In essence you recognise that you have a painful emotion. You do not get involved with it, but simply note its existence. It is there and you can note the effect on your body, your emotions, your thoughts. You note it, recognise it and allow it to pass. This takes a bit of practice, and some training in mindfulness meditation can be helpful.
Self-talk, especially rational talk can be useful. In this you can for example tell yourself that you are in no danger now, that you have control where you never had it and so on.
When experiencing flashbacks it is useful to become aware of your surroundings, of becoming aware of the feel of the floor, the chair, how your clothing feels on your body, what you see around you and so on. It is then helpful to tell yourself the date and time and place and to note that you are safe. Tell yourself that you are only remembering the traumatic event, it is not really happening. Although you are then painfully aware of the event, force yourself to become aware of your current reality.