Hi Gail,
Usually, for tablets to work, they have to dissolve in the stomach and be absorbed in the intestines so that they enter the blood. If you're bringing up recognisable tablets that's not a good sign. Copepod's advice about liquids is good, i think they work faster because they don't need to dissolve. There's also the posibility that your psychiatric meds could be given as liquids. (Fluoxetine is deffinately availible as a liquid, i think paroxetine is too.)
Have you had the nausea for a while? Could it be a side effect of the metformin or pioglitasone?
Can you talk to your doctor of pharmacist about the number of pills you're taking, 20 is a lot to handle (and swallow). For eaxmple pioglitazone and metformin are availible as a combined single tablet (Competact from Takeda), that might help.
Rachel