 [ Symptoms ] i od meth 3 days ago but still feel off if an overdose kills someone does it only occur immediately  i am concerned because i am not sure if how i feel is withdrawal or something potentially fatal like maybe slow kidney failure is that possible days later i am periodically a little shaking throat feels a little tight my heartbeat seems a tad off and a little tight temperature is 96 5 my comprehension is somewhat distracted e g when reading textbooks [ Disease ] sure gas x is the brand name for a medication called simethicone its primary purpose is to treat gas in the alimentary canal stomach and intestines tums is a brand name of calcium carbonate chewable tablets calcium carbonate is used to treat excessive acid in the stomach you should not run into any problems using both of them at the same time however do not do this over the long term if you are having chronic issues with pain and bloating see your doctor best wishes to you