In general, ADHD symptoms decline as a child matures into adulthood, but there often can be residual problems. It's unusual for symptoms to get worse, however with home schooling, you likely had a more controlled, lower stimulation environment. College is much more stimulating, and that could make it more difficult for you to focus. Stress can also exacerbate symptoms, as can depression and/or anxiety. If you've never been diagnosed with ADHD before, it's more likely that symptoms you are experiencing now would be related to something else, either physical as you suggested or emotional. I'd check with your school about any learning assistance and/or health type resources to see if you can get a more definitive answer about cause. That will help with figuring out how to target the symptoms so you can continue with your studies most effectively and efficiently.

All that being said, I was diagnosed for the first time as an adult. When I entered grad school, the stress and the level of challenge presented were more than my adaptive skills could handle, and symptoms emerged and started causing real problems. Looking back to childhood, there were indications of ADHD then, but it's always been mild, and I'd most of the time been able to compensate.

Hope this helps, and take care,

gg