Hello. First let me offer you my condolences. I know how hard this is. I certainly do. It tears your heart out.
You said "he was bleeding in his stomach". Did the vet tell you this was internal bleeding from the Spleen and/or Liver? Did your dog have a diagnosis of Hemangiosarcoma?
Sadly, Hemangiosarcoma is increasingly common in dogs. It is quite often the cause of sudden internal bleeding and collapse.
If it was this your dog had, then there is NO CURE.
A seemingly healthy dog can suddenly collapse from it. Their bellies fill up with laeking blood from ruptured tumours and this compresses the lungs. That is usually at the stage when nothing else can possibly be done to help them.
So in my opinion, yes you did absolutely the right thing.
Blessings to you and to his lovely Soul.