Lelly, welcome. I'm so sorry for the loss of your baby. I know the devastation and agony you're feeling. What you wrote is so similar to what I've been going through for the last 6 weeks, right down to "9 year old baby boy." I too have never felt so heartbroken either, and miss my baby boy to the depth of my soul.
No, it's not awful to feel that this is more painful than the deaths of humans we know - it actually makes a lot of sense. Someone said the same thing to me right after I lost my Buddy, and noted, "Animals are more kind, aren't they?" And my husband added, "They love unconditionally." This is a safe place to express how you feel, and be understood. Please be sure that you're eating, doing your best to get decent sleep at night, and keeping occupied during the day as much as you can, with work or other things - even if those things feel meaningless now. Taking care of yourself and having a routine will help you get through this... one day, even one hour at a time. Sending you hugs...
Cindy (Buddy’s mama)
My baby Buddy 5/4/10-3/7/20, rescued March 2011 My sweet Mandy 11/27/91-11/2/10, rescued November 1992 My beautiful Barney 4/28/73-9/7/92, adopted May 1973