Sammie: My sympathy goes to you, I know the feeling all to well as my 8 year old beloved cat died this year (the saturday night before Mother's Day). We also had no warning signs and had been out before it happened and within 10 minutes she was no longer with us. We also don't know what happened and I didn't want a vet to find out, so we found a special place in our garden to put her to rest and my DH searched for the perfect rose bush to plant over her (an unusual rose called Oranges & Lemon's as Shilo had very unusual marking) and we had flowers this spring - summer. It is nice to know that in some way she is still with us and I'm sure your beloved pet will be with you always as well.