Tip - Solutions for Cooling Down My Memory Foam Mattress? — Good Questions

Q: I have Graves Disease and that makes me generally warm, I have a memory foam mattress, and sleeping on foam is ridiculously warm. I wake up so over heated I have to get out of bed and cool down. It's really impacting my sleep. I want to buy a new mattress, but don't have the money so I thought maybe there could be some sort of mattress pad that might insulate me from the foam. I bought one, but despite the claims, it doesn't insulate any better. Any suggestions?