Yellow coated tongue and sweet taste after eating

I'm in 22 weeks through my pregnancy. Recently went to see doctor for excessive bloating and gas with constipation. But i feel better after completing my course of medication. Since then i have been having weird sweet taste at the back of my tongue. And it was coated with yellow residue. I have been trying to use tongue scrapper to scrap off the residue every meal but it will appear back right away when i eat. Has anyone experienced this weird taste before? Pls share your experience and remedy if any TIA! #pleasehelp #advicepls #FTM