I am on anastrazole, an aromatase inhibitor that depletes estrogen and also on herceptin infusions due to HER2+. Neither of them have affected me mentally. I do still have chemo brain that cause some short time memory problems and general "spacing out" from time to time, but that was from my chemo regimen earlier this year.
I've also had both peripheral edema (swelling) and neuropathy (numbness), but again these were from chemo, not the drugs I am on now. My edema has only been off and on and short term use of Furosemide has controlled it. If that isn't working for you, I would suggest you talk to your doctor about switching to a different diuretic. I doubt that losing weight will make a difference (other than the fluid weight your are carrying with the edema), but exercise might. Check with your doctor about that as well. Also try to eliminate as much salt as possible from your diet. Canned and packaged foods are notorious for being loaded with salt.
The biggest long term risk with peripheral edema is that is tends to be a symptom of congestive heart failure which can be fatal.