@riflemanz64 I hope you won't mind me second guessing some here. We don't know each other, and neither of us is medically trained.

Your swollen stomach may be just that....swollen. As in 'ascites'. This is an accumulation of fluids in your gut from poor heart function. Usually there might also be some swelling of the feet tissues and ankles. Does this every happen? Or, if you're putting on weight with all this activity, then it's either drug-encouraged (medicines) or it's your body telling you it cannot use all the calories it is being forced to store....as fat. You may have to reduce your carbohydrate and/or fat content in your diet by close to half...at first, say a month or more to see what happens, and then adjust a bit upward or downward to tidy up your approach to a reasonable goal of weight loss. Figure that out as well: how much weight do you think might be a reasonable, attainable, and sustainable goal? Ten kilograms? Two? Fuzzy notions about a direction are poor motivators and metrics for goal-setting which, in turn, is a necessary motivator for most weight-loss programs. Get specific, with real numbers, and then figure out how to get 'there'. Seek advice if it will help. Or read lots. YouTube videos, several from different hosts, will help you to decide how to do this the 'right way'. BTW, that word sustainable is important. If you rebound in a year and gain it all back, you have not done it properly. You must be comfortable with the goal, and then how you get there....AND...stay there.

Finally, and I remind you that I am nothing like a doctor of medicine. No training or experience. And I'm not totally familiar with diltiazem except it is a rate control medication and meant to curb calcium channel activity in the myocardium. It helps to reduce the force of contractions in addition to how fast those contractions come. Reducing their force means less blood pressure, so like metoprolol and bisoprolol, they can often be prescribed for incipient hypertension. However, some patients begin to enter bradycardia territory with heart rates near 45 BPM, even lower. This doesn't allow the body to clear itself of gravitationally held fluids and they build up, possible as ascites, as I mentioned. But your shortness of breath, loss of energy, etc might, could be, should be investigated...that it isn't bradycardia from that, to me, high dose of diltiazem. And for God's sake, don't stop any prescriptions! Check this out with your prescribing physician.