Sometimes I can't breathe so I start shaking and sweating profusely. Am I just being incredibly nervous?

Maybe. While these symptoms may be related to anxiety, you should see your health care provider to make sure you do not have a more serious health condtion.
It sounds like panic. If this is new for you, ruling out a physical condition is a good idea. Panic attacks usually start earlier in life. At a first glance, this could be a panic attack, which is treatable. You will have to learn how to deal with them, what triggers them and what to do about it. It may also be a temporary reaction to something going on right now in your life. But it could also be a physical disease.
Panic. It sounds like you have panic attacks, which in a sense is just being incredibly nervous. Anxiety causes the release of the fight or flight hormones which cause trouble breathing, shaking and sweating. Have a psychiatric evaluation as this is easily treated.