Riding small-small is called cross-chaining, and is not recommended. On a double chainwheel bike at least the smallest and sometimes the next smallest should not be used. On a triple it's more like the 3 smallest. Nevertheless, the derailleur pulleys should take up the slack at least, if you have not made any changes to chain or derailleur. The spring on the pulley cage may be broken or weak. You need to get in-person help at a bike co-op or bike shop. I’m happy to help further over the phone at https://www.6ya.com/expert/donald_f2ed37026a3ac881