Why Do I Get Heated Up So Much With Excessive Sweating?

I am 68 years old and for abaout 3 years I have been excessively hot. I do sweat but now a lot. Whenever I do some work and I am walking, moving my arms in particular. The overheatedness starts. I do not look like heatstroke. I look very red in the face. I have the feeling that I just cannot go on doing anything. I sit down. About 20 minutes later (usually w/a fan or a ice pack) I am o.k. and back to it again. Family not understanding, employer not understanding. I also have excessive loud belching (like my father when he was older( I have been told I have GERD and it has been treated for 16 years), he also was excessively warm. My Paternal grandmother also had similar issues. Help?