The only way to know now is to have a pregnancy test. Your own blood flow will sound like a heartbeat. Your stomach is located up high under the left breast, so I am assuming that you are referring to your lower abdomen. Lumps from gas and feces can accumulate in the colon and even create sensations of movement. Also, cancer and other health problems can create hard lumps. Cravings and weight gain can be hormonal and age related too. Take a pregnancy test and see your doctor.
youngj37: The birth control pill prevents ovulation, not periods. So she will have a period at the end of the 21 day pill cycle. There is no such things as a pill to induce a period. Periods come when the hormone level changes. The contraceptive pill can cause nausea and weight gain (side effects), especially when you first start taking it.