It depends on the type of anxiety and the severity of your anxiety.
If you have
separation anxiety, then you may not even attend school at all, as you are concerned about the safety of your parents when they are away from you. If you do go to school, then it becomes a problem with your parents dropping you off, as you cling to them and have meltdowns if they don't take you with them. Eventually, after much cajoling from teachers and other school staff, you resign to staying at school while your parents slip away. And while at school, you are distracted by your worries about your parents, hoping they don't get into an accident, and wondering if they will pick you up or not.
If you have
social anxiety, then you have a fear that in crowds of classmates at school, they will make fun of you or scrutinize you. If your fear of being socially ostracized is severe enough, then you will likely avoid school. If you do go, then you resort to safety behaviors to protect yourself, like stand in a corner, not make eye contact, avoid conversations, fiddle with pockets, distract yourself with your cell phone, etc. And if you do attend school, you are so worried what people think of you that you can't focus and your school work suffers.
If you have
test anxiety, then you have the extreme fear of test situations, as you do not want to embarrass yourself. So when you are about to take a test, you might experience a panic attack, as you work yourself up with anticipatory anxiety about how you will do on the test that you get severe anxiety symptoms. This then severely affects your ability to complete or do well on tests.
If you have
health anxiety, then you either miss many days of school, as you are sick (but without physical causes), or if you do go to school, you spend much time in the bathroom or at the school nurse's office, as you are worried about having or developing a serious medical illness. Because of your multiple absences from class, you do not perform well academically and your grades decline.
If you have
panic disorder, then you might have panic attacks that occur at school, and can be quite disruptive to your classroom. When you are not experiencing a panic attack, then you may spend much of your time anticipating when the next panic attack will occur. Suffice it to say that your school performance will suffer, as you are so wrought with anticipatory worry or may be experiencing panic attacks at school.
If you have
OCD (obsessive compulsive disorder), then you will be distracted by your obsessions and compulsions. These can be quite disruptive to your classroom, and also cause you to be distracted by your anxiety symptoms. Hence, your school performance suffers.
And if you have
PTSD (post traumatic stress disorder), then you will be distracted by your flashbacks about the trauma you experienced. You may also avoid certain situations or people (bullies) who remind you of the trauma. You may also have hypervigilance, where you are constantly on alert for any danger in the environment. If you have active PTSD, then your school performance will likely suffer, especially if your triggers for the traumatic event are present at school (ie the bullies are in your classes).
So as you see, having anxiety in school can be quite disruptive, and can cause you to have poor school performance. The good news is that there is help for any type of anxiety you may have. Please visit the rest of
AnxietyBoss.com for more information and help on anxiety and stress.