I know exactly how you must be feeling (((BIG HUGS)))
In August 2008 I lost my whippet Tina when she fell into a flooded fast river and drowned
For months afterwards I did nothing but blame myself and cry and in May 2009 was off work for three weeks with stress. Thankfully with counselling and a few Happy Pills I started to pick myself up and stop blaming myself all the time.
Last year my wonderful cat Domino passed away and even now I still feel a huge loss and still shed a tear or two when I look at photos of her.
The main thing to remember is that it is perfectly normal to grieve over Peanut (((HUGS))) Folk who say he was 'only' a dog or expect you to just 'snap out of it' have obviously never shared that bond with a loving canine.
I only had Domino 100 days (she was a rescue - I wrote about her in the Other Pets section) and even though I am now owned by four other rescue cats SHE is still the one who sticks out and has made the most impact on me.
It's still VERY early days for you so allow yourself to grieve and don't bottle up those tears - let them out! I now, if I'm feeling low, allow myself to have a really good cry for 20 minutes only and then take a deep breath, dry my eyes and carry on with my day. With time you WILL start to only think of the good times with Peanut and be able to look at photos of him without feeling as though you've been ripped in half. You'll still feel a little pang of sadness at his loss but with time it will become more bearable (((HUGS)))
In the meantime please DO keep posting in this journal - writing things DOES help (((HUGS)))