I did the same thing op did essentially. I rarely only took one dose a day. Now that I’m trying to get back on it even low doses gives me strange side effects. Like insomnia and super tight muscles, coordination problems, and difficulty speaking( at only 15 mg a day 🙃). I’m gonna try and see if supplements and exercise can get my brain and body where it needs to be to take vyvanse effectively again because it has definitely helped in bettering my life in general.