How long after the end of treatment is it possible that side effects of Metronidazole occur?

Yellow raid on the tongue, although it may cause surprise and anxiety, is not a sign of serious health problems. In this case, it is rather associated with taking an antibiotic. The remaining symptoms described by you - low pressure, lack of energy, dizziness may indicate deodorization of the body. I suggest paying attention to the amount of water drunk and, if possible, increase it to about 8 cups a day. (The water balance does not include such liquids as coffee, black tea). If you do not feel an improvement in well-being within a few days, I encourage you to consult the attending physician, who will order basic tests (e.g. blood count, urine test, glycemia, sometimes abdominal ultrasound) and on this basis will be able to determine what is caused by malaise.

I took metronidazole in tablets. 3x1 dose 250mg. The treatment lasted 7 days. After the treatment I feel like I feel so without strength, but not without energy, just some kind of tired of life, I have a very low pressure and I feel in my body as if I was something crushed, the tongue covered with a yellow bloom and thus some strange aftertaste in my mouth, sometimes such a feeling as if I had just come down from the carousel or was strutting with something.