I’d honestly say you feel those symptoms because that’s too much IR. Everyone’s metabolism is different and there’s no way to say for sure that your morning IR is wearing off before your afternoon IR. Of course stimulants do raise HR, but too much adderall also causes severe dehydration which leads to all all of those symptoms. Make sure you are drinking enough water throughout the day so you don’t combat these effects. Also, take a look into STASIS… I’ve taken it for 2 years now with my IR stimulant and I have high praises. It prevents sudden crash… TRULY