Brief Answer:
No worries. Symptomatic care. Stomach flu or functional bowel decline

Detailed Answer:
Thank you for asking

I read your question and i understand your concern. monthly episodes of vomiting and belching self resolving in nature lasting for a day or two appear benign in nature and may indicate some functional bowel decline. With advancing age these issues may happen. However only a day or two lasting and then self resolving may give a suspicion of stomach flu, a food poisoning, or exacerbated gastric discomfort due to gastritis or reflux issue.

I would like you to take some pepto when it occurs, take some motility enhancing medications and drink plenty of fluids. Eat small frequent meals and use some probiotics to help the flora balance as that will help the belching. Yogurt is the best natural probiotic and should be prefered. Also peppermint helps with the spams and discomfort and will relieve the vomiting too.

If the problem persists i would like you to get evaluated to be on the safer road. Although the illness looks benign and nothing to worry about.

I hope it helps. Take good care of yourself and don't forget to close the discussion please.

Regards
Khan

---