Hello moms, Happy New Year ? It will be 8 months soon?? Time flies so …

Hello moms, Happy New Year ? It will be 8 months soon?? Time flies so fast, it's like yesterday I was crying and asking for your advice etc. Now I'm starting to understand my little one ? on Gv + feeding, we eat everything. Yesterday I ate banana and this morning went to the toilet, black stool + sour smell or maybe I just think so ?? Still teething and appetite is not as before. Experts in poop, can you say that this could be? I myself think it's because of the banana? Should I talk to a doctor?