Trying to get in the groove

This may seem like a dumb question-but are some people just not made to work out vigorously all the time? I have only made it through one program (Benchmark) in a reasonable amount of time (it took me 6 weeks) since I started in June. I have tried other programs but I end up getting hurt or sick and it throws me completely off track to where I need to start over! I’m a healthy person with no known underlying immune issues or health issues, I’m mildly overweight, and I’m insulin resistant but that’s it. Anyone else finding it hard to find a groove? I really want to make some real body changes as well as contribute to my mental health by getting regular exercise. Thanks!