How can I tell if I am lactose intollerant other than bloat?

Diet or enzyme. Lactose intolerance is very common. It can cause bloating and/or diarrhea. The best way to test for it is to try a week of strict avoidance of all dairy, and then a week on dairy to compare. Then repeat to see if tis reproducible. You can also do a breath hydrogen test, or just try enzyme (lactase) supplementation.