Which Kratom do yall recommend?

Currently been taking the gas station 7oh 15 mg single pills i now have a tolerance and no longer feel that energy anymore, i hear extracts aren’t as good. i generally take 1/2 in the morning with a low caffeine energy drink & 1/2 at lunch time with little to no effect thanx in advance. What am i doing wrong. Someone help me get back to what i was feeling before. Am i using the right strain?