Swelling can be serious… or not. Best to get it checked out. If you have blurred vision, swelling on one side only, dizziness or if you are drinking loads of water and not needing the loo frequently, I would go straight to the ER.
However, water retention swelling can be totally normal. I currently have elephant feet and kankles (very attractive) and my doctor isn't concerned at all because my BP is normal. It is the middle of summer where I live too which isn't helping.
Hope yours isn't anything serious.