What Causes Drowsiness Along With Diarrhoea And Vomiting?

hye doctor gud morning.... well im 51yrs male n diagnosed as diabetic for 10yrs and consuming tab. metformin 500mg tds nad early stage of hypertension and on tab. amlodipine 10mg daily. past afew day im not feeling good feeling drowsy on and off where i ve noted my glucose level dropped up to 3 to 4 reading. advised by dr to take glucose drink when ever feel drowsy and sweating and to take medicine after meal....Past two day im having black colour loose motion and vomitting anf felt uncomfortable stomach with bloating.....plz do advise me doctor....thanking you in advance