Yes, you should be concerned. Sleep deprivation can lead to illness and bad decisions. At 19, you need 6 to 8 hours of restorative sleep every night to be at your best. But from what you told me, it makes sense that sleep aids aren’t helping. Your sleeplessness seems to be a symptom of a larger problem. You are focusing on the sleep. I’m thinking you should be focusing on what it is that is making you so anxious about your future, your schooling, and your choices. You aren’t able to shut down your worries at night so of course you can’t sleep.
I suggest you get at the root cause of your sleep problems directly. Most colleges have a career center. Please make an appointment to talk to a counselor there about your school and career choices. If there isn’t a career center, consider whether there is another resource on campus such as a counseling center or pastoral counselor. Many teachers are also happy to talk to an interested student. You might also find this article helpful.
Meanwhile, there are some things you can do about sleep. Get regular in your sleep habits. Go to bed at the same time every night. Do not let yourself take naps. Eliminate caffeine. Read and study somewhere other than in your bed. You want bed to be associated with sleep. If you can’t sleep, don’t toss and turn. It only makes a person more anxious. Instead, get up and write down your thoughts and feelings. Then go back to bed.
I think a combination of dealing with your worries directly and taking charge of your sleep hours will help.
I wish you well.