Are you on any meds for anxiety? Some meds can help with regards to flashbacks. Do you have therapy? Often the combination of the two can be helpful.
I understand about freaking out and also how tiring it is once you have calmed down, sometimes it takes over the whole week. You have to just ride it through and let it pass, also certain types of avoidance obviously isn't always recommended but there are times when avoidance helps you to cope - do whatever you have to do. The person who touched your shoulder may have been of a certain gender that relates to the trauma and if so your reaction is understandable even if it wasn't someone of that gender being touched may be something you feel uncomfortable with, once again absolutely fine and something that you will deal with over time when you are ready.
Aside from cleaning, there may be something else that you can do to work off that energy so that you aren't concerned with waking the dogs etc and you can just focus on feeling ok again. I hate to recommend jogging or running because my tactless father just coldly says 'go for a run' and I know that doesn't help me...but exercise obviously can help a little. Definitely something where you are moving around. Perhaps think of one more activity you can do apart from cleaning that is something that you know that you don't mind doing.
