My husband Colin used to get blackouts in the 1970s, probably from post-traumatic stress syndrome (before anyone knew there was such a thing). His all-time record was somehow making his way from Beirut to New York over a period of several days before he "woke up". Still has no idea how he managed it, much less why.
So, in the scheme of things, you can at least be assured that it could be a lot worse! And it's likely to get better in time, especially if you have support from family and friends. Be sure to get as much help as you can from your GP.
Anxiety UK has some useful information and help for PTSD. There's also a
PTSD website that was set up for ex-servicemen but is open to civilians as well.
Support groups can be really helpful, so don't be afraid to join up. I was sceptical about them until I joined a couple (for carers and for Asperger's syndrome) and found them... well, supportive.