Keep Getting Headaches From My Strattera Meds 18mg, I Also

Question: keep getting headaches from my strattera meds 18mg, I also take 90mg XXXXXXX for cholesterol (it's not super high its 96 I just have a family history of high cholesterol and diet and exercise didnt decrease fast enough.) I'm 23. I took straterra when I was younger and taking now that I'm older before was on adderall xr 30mg. plus fast release at end of day had to stop bc was having withdrawal symptoms. I'm not a druggy I just was awful about taking it on time ,forget to take, or couldn't pick up medication sometimes. I dont get headaches when I take straterra at 11pm by itself but I get headaches if I take a my cholesterol meds or even if I take 1hr apart from cholesterol meds in afternoon (2:35 to 3:45) I've tried taking 2 at night bc I mis interpreted directions from dr and what was on pharmacy bottle. said to increase after 5days so I started taking 2 18mg pills at night for a week and a half, went back to 1 at night. tried during the day for 2 weeks but kept getting headaches. I just dont want to have withdrawl symptoms again bc of random times taking pill and dose increase n decrease. km just tired of headaches and I dont know if it's ok to just stick to at night from now on. I cant meet w my dr until XXXXXXX 20th I've been on pills for 1month and a 7 days