Anxiety can cause all sorts of feelings and 'symptoms' in my opinion. I often feel 'out of my skin' when I am stressd. Are you going through changes in your life right now? Are you under a lot of stress?
Ally, this is ironic you posted this. Please tell me if these symptoms are also going on with you too....I've been going through the same stuff. I'll get really weak and tired and struggle to keep my consciousness and my head will start falling like when you nod off and then i'll jump back awake. Is this what is going with you too? Agreed with remar. Just see your doc for a full check up and yes if he finds nothing then it might very well be depression. I told my mom about this out of concern too and she had told me allergies can also cause a person to become severely fatigued like this. I don't know if it is causing these passing out sensations in us or not though. Seems like allergies are pretty bad this year though. I've never had allergies in my life until this spring @ 26 years old and I'm telling you I've never felt so run down, congested , sinus pressure , felt so sick and had this many migraines repeatedly all at once at all until this year.
I would recommend seeing your Dr for a full check up. If he finds nothing physically wrong, it could be depression.