Does this sound like GERD? Hiatal hernia or anything similar?

No definitely not GERD from the symptoms you describe. You need to review your diet and exercise to improve your digestion and general well-being. At least 20 minutes each day gentle exercise (walking, jogging, swimming, aerobics) but do more if you can. If you are bloated then take a mild laxative. A hernia is something only a Dr can confirm