Speaking from experience (former faculty member), your anxiety (performance anxiety) is not unusual for people who are starting college after a break from high school. First, let me say that I admire you for returning to college. It is a different type of decision for someone who is 17 versus someone who is 27. But, you have the something that a 17 year old does not have . . .experience and perspective. These are both extremely strong attributes.
May I suggest the following? You need to look at college definitely as a means to take a giant leap away from a dead end job. You also should consider it as a means to reframe your anxiety. Anxiety produces adrenaline, so let reality brain use it to help you to accomplish your goals. Rather than let the adrenaline stay with anxiety brain and produce performance anxiety, use it to develop skills to accomplish your goals. Seek out Student Services to help you with any type of study skills you feel that you may need for your return to school. Consider the courses that you are taking so you do not overload yourself at the beginning (rather than taking 6 courses when you only need 4 . . .start slowly and ease your way in . . . nothing succeeds like success as the saying go and then next term, you can take more if you feel comfortable). If possible, find a study buddy so you have mutual support. Also, some colleges provide free "mentor-tutors" who are students who have already completed the course who volunteer to mentor other students through the course. Check it out . . . nothing gets rid of anxiety more quickly than to know what to expect and have the reassurance that you are progressing. And, please, do not view tests/exams as the be all and end all . . . .yes, grades are important, but I have counseled many students who needed a semester to adjust to the style of college / university system. Cut yourself some slack and do not value yourself based on the grades received . . . you can always improve your grades with different study methods, but it is much more difficult, especially those with performance anxiety (myself included) to recover from a hit on our self-esteem.
You're going to be fine . . . .remember it is a process and you will not be trapped in a dead end job because you have already shown your strength to take the step to return to college. . . . let us know how things are going .. ..take care, kc