Grief after dog's death.

I need your help, please... for peace of mind so I can sleep and live with myself.

My dog, Barbie, was the world to me. She was my best friend and child- she passed away on Easter Sunday this year- a week before her 11th birthday- she was like a puppy hours before she died- energetic and sharp... I don't understand what could've happened, but I will give you her background.

She's always been healthy- i've always kept up with vet check ups, vaccinations, grooming... even had her anal glands emptied once every couple of months. She was on Natural Balance food then Blue Buffalo as a senior- she had regular exercise but above all- tons and tons of love.

About a month before she died- she was chasing around our other dog around our house- she had slipped and ran into a pole which caused limping and a rather large lump on her back hip- we took Barbie to the vet immediately- the vet scheduled an ultra sound and found that she had muscle separation and a bad hematoma- he told us it would take about five months to heal- put her on Vicodin because she could not tolerate Metacam- I only gave her a half of a Vicodin when her pain seemed to be very very bad... because I know dogs have trouble digesting acetominophin... she would have her good days and bad- and tried her best to run (which she LOVED doing) but I just couldn't let her do because I wanted her injured hip to heal.

On the morning of Easter Sunday- Barbie seemed ok, but was limping around more than usual. It was a cold rainy day- so I gave her half of her pain medicine and kept a close eye on her. She ate breakfast- went for her morning walk-and was excited to get her glucosamine tablet... she was definitely slower than she had been- but I thought it was just pain... as the day went on- she became more lethargic and refused to even eat a treat. My girlfriend was laying on the floor with her, when Barbie tried standing- her back legs were dragging on the ground and her head whipped back- like she lost her balance... she seemed disoriented. We carried her to the car and had a horrible 30 minute drive to the Emergency Vet.

In the car she seemed like she was having trouble breathing- I looked at her gums, they were a white/grey color. She laid down (something she NEVER did in the car before).

When we arrived at the vet- I carried her in... the vet tech took one look at her and said she was in shock and carried her back immediately- awhile later the vet told me that he was extremely worried about Barbie- her heart rate was very high, and her BP was very low. He asked if she could've ingested any poisons- I knew it was impossible- she never left my sight- even outside for a walk.

I had to sign papers- due to financial concerns of the vet- I didn't care- I told him to do whatever possible to save my baby- he pushed fluids, gave her plasma, oxygen- everything... but barely any changes. Her red blood cells were very low.

He came back a final time- after giving her ultra sounds... he told me that something looked funny in her back- he suspected she had a tumor on her kidney that had burst and was causing her to bleed internally- he SUSPECTED it... which I guess means he didn't know for sure. He said he could give her a blood transfusion that would just make her strong enough for a surgery to stop the bleeding- but there was a large chance she would pass during surgery (the thought of my baby dying with strangers killed me) he said if he stopped the bleeding, we'd still have to worry about the tumor-- he recommended euthanasia- all because the surgery would run up to $10,000 (I didn't care about money) I would've paid!! He said if it was his dog he would put her to sleep... I had to agree. When we went back to see her- around her eyes (which were usually pink) were white... she gave me a kiss- I noticed her tongue was white. She whimpered (she always cried when she saw me) and wagged her tail... they took all of us back into a room- administered the dreaded blue shot- and she fell asleep, forever, in my arms.

The thing that confuses me- a few weeks prior- she had to have one of her teeth extracted because of a slab fracture (i gave her a bone that was too hard... i know... bad mommy) she had a lot of blood work done for surgery and EVERYTHING was perfect- just three weeks before- if she had a tumor on her kidney, her blood work would've shown something wrong, right?

I always promised myself I would do all I could do for my baby, I made a silent vow upon adopting her- to protect her, and keep her healthy- I feel like I killed my best friend. Did I do something wrong? Did I accidently kick her off the bed at night- pick her up wrong? which caused internal bleeding? I read that internal bleeding often happens with accidents- what if one of us stepped on her at night and didn't know it? I feel awful- maybe I should've done the surgery? I just want to know if this is a common thing- if it sounds funny to you? I have given you all of the information I know- she's had tons of xrays and ultrasounds on her hip... I just don't know what to do. Our bond was immeasurable and now she's gone- and my girlfriend and I are blaming ourselves. Barbie took my hearth with her when she passed- I feel so empty... but when I do feel it's guilt and absolute sadness. Please help!