That's not necessarily the deviation of practicing qigong, because you haven't practiced for many years, and your sense of qi is gone. If you don't burp, you will feel uncomfortable. Maybe it's your stomach. Maybe your liver is not good. You'd better check it.

If it is really qi stagnation, do more double return air to exhaust the gas from Yongquan point until it is comfortable.

If you insist on practicing qigong regularly, you may have been better long ago.