My 7 year old golden had his spleen removed 6 weeks ago due to a large bleeding hemangiosarcoma tumor. We know he only has a limited time left. He's been acting fine and is otherwise healthy now. he is on steriods for a foot infection they think is auto immune related triggored by the surgery. He threw up 4 times last night, once earlier today and again this evening. He's still drinking water and when he threw up this evening he ate it back up before we could get to him. Any ideas why he is doing this???