I was taking Teva for the past few months and I felt exactly like you feel. I told my doctor and I went back to Vyvanse and I feel much better.
I experienced ineffectiveness with another generic adderall. I didn’t return the pills, my doctor wrote a prescription for vyvanse and I disposed of the other pills. I am thankful my doctor treats me like an adult and understands this happens. I am sure some doctors might accuse their patients of hoarding pills in a situation like this.