Hello there I think you need to see psychiatrist
Calcium can cause git disturbance , upset and leads your heart beats to really quicken
But also you have to find out is there any other factors for this stress
And if you are confirmed to have panic attacks your doctor will prescribe benzodiazepines as short relieving and antidepressant for a long term action
First of all, you shouldn't be taking Tums at all and certainly not on a regular basis. Tums is a form of calcium that isn't well absorbed, and while it can provide some temporary heartburn relief used regularly it can cause rebound acidity and also leave calcium deposits hanging around when you don't need them. Second, a bloated stomach is caused by eating too soon before going to bed, insufficient exercise, or your diet. Solve the problem, don't medicate it. If you need to, try some aloe vera juice or DGL for the occasional problem. You might try doing some abs before going to bed to break up that bloated feeling. Now, I don't know that any of what you're feeling has anything to do with the feeling of a racing heart; that may be anxiety about something in your life that is arising when you ready for sleep, which means the next day is coming. Anything you're concerned about?
Perhaps you can Google and find some other way to help relax, or maybe find how to do the breathing so it works.