What will happen if you go too long with an anxiety disorder without treatment?

And is it highly possible to confuse one with OCD? Thanks.

Negative emotions (like sadness, stress, anger, etc.) causes your Serotonin production to be low; when your Serotonin level is low, you are more prone to getting Anxiety, Panic Attacks, Depression, etc.

Medication like Antidepressants (SSRI - Selective Serotonin Reuptake Inhibitor) helps to boost Serotonin level.

But there are natural ways to do it without medication. There's this strange herb called "St John's Wort" - it is said to be more effective than Prozac. No, it is not for mild depression only and ignore those sayings. In fact, it does help anxiety and panic-attacks as St John's Wort works like prozac. Other natural ways will be exercise, diet, more exposure to light, etc.
The problem is that, even if your Serotonin is balanced... you have that "learned behavior" in your mind. You need to break that initial cycle to destroy that learned behavior - Cognitive Behavior Therapy (CBT) does this. A technique that you can use without CBT will be Distraction... There are several other techniques to help cope them!
Ok, to use Distraction: Firstly, try to....

Extracted from Source.

Obessive Compulsive Disorder is a subtype of an anxiety disorder. Without treatment and council, one will only make themselves more anxious. It is possible that if their stressor (thing causing anxiety) is removed than their condition may improve. Most people with an anxiety disorder suffer from many stressors, not just one, so treatment is important. OCD is a cognitive and behavioral anxiety disorder. The obsession is the thought and the compulsion is the behavior. A behavioral therapist would suggest changing the patients thought process in order to change their behavior. In extreme/rare cases patients may commit suicide because they feel it is the only way to escape their anxiety. Treatment is a necessity.

I look at my chronic health problem more as something that doesn't go away but I learn how to control it. When I start to make the wrong choices I end up sick again. I have found that easy meditation and yoga helps me keep control of my health even if it does come back to haunt me every now and then.

Depends on what the anxiety disorder is.