Insomnia and stims

Anyone experience insomnia in few days into stims? The first couple of days they made me really tired and I had no trouble sleeping. However, the last 3 days, although still making me tired, I only sleep 2-3 hours and then wake up and can’t fall back asleep. I mentioned it to my nurses yesterday and after looking confused they said they never had anyone say they weren’t sleeping enough (just that they were sleeping/tired more than normal). I’m not overly stressed or uncomfortable so the only thing I can think it could be would be a side effect of the stims. Anyone else? Any tips?