I think this is more of a “should I see a doctor?” question than a “should I stop attending Mass” question. If your breath is that bad, then you also are seeing your life impacted at work, when dating (or in your marriage), with friends, etc.
Bad breath can do more than impact your worship, social and professional life. It can be a result of bad health. You may have something serious going on. It could be anything from tooth decay to acid reflux (which can cause esophageal cancer), if you still have your tonsils you may have tonsil stones which are incredibly foul (I had them before I had my tonsils removed, so I know from experience). Please see a doctor.