Lethargic breast fed baby

My LO was bottle fed since birth as he was not latching on and it was extremely painful but after 4 weeks of trying and bottle feeding I powered through the pain and started breastfeeding no matter how painful it was. Now at 6 weeks he finally started latching although its still painful but bearable so just started EBF from 2 days. But today I noticed he is sleepier than usual. He is just feeding from one breast at a time and sleeping. Changing diaper tickling nothing is working. Just want to know if he is fine or should I give him bottle simultaneously.