Do I have Complex PTSD?

Hi, I have had a prolonged traumatic stress for 2 and a half years. I have searched online and I think the symptoms fit me. However, my symptoms also fit that of depression.
I get really irritated, sad, moody, obsessed whenever I think of the traumatic experience and then cannot get it out of my head for days. Other days (very few) when I don't have these thoughts, I am fine. I hate it when the thoughts invades my mind Do you think I have C-PTSD in this case and not depression?

Also, is Complex PTSD something that can be diagnosed officially? If I go to GP (I am in UK) will there be some kind of treatment to hep me overcome it?

I'm sorry but no one on here can diagnose you as having cptsd. I don't know if you would be diagnosed with it either as an offical dx, I've heard it's not popular, but the only way for you to find out is to see a doctor who specializes in trauma.
To have cptsd i know you have you have repeated traumas and reexposure to traumas.
Yes there are treatments.

I also live in the UK and when I was having problems I went to my GP too. I'll be honest here, it takes a LOT for them to diagnose PTSD. My doctor tried to say I was depressed, schizophrenic, bipolar, borderline personality but none of these things fit for me and the symptoms weren't mine. It wasn't until I looked up mine and went to my doctor that he agreed it was PTSD.

From what you describe, you could be either. But PTSD isn't thinking of a traumatic experience so much, it's actually having flashback. The key feature of diagnosing it is that you have flashbacks in which you zone out and feel as though you are in the traumatic moment. It's unlike a nightmare as it's not thoughts, it's you feeling every touch/taste/smell etc that you did then and reliving it. I haven't heard them last for days before but anything is possible I think!

Someone else could probably explain better the difference between PTSD and C-PTSD because I think that's even harder to diagnose a difference so I can't help too much with that. Either way, there are treatments to help.

Please bear in mind I'm just speaking from experience and nobody can really diagnose you but a doctor or a trauma specialist (which I'm definitely not!), I'm just throwing in my two cents of what I know from having it a few years. Hope this helps in some way though!