Emily,
I have a lot of the same symptoms as you so I can relate. I've been having the constant headaches for over 5 months now (mine go away during the spring and summer usually), tried some meds but quit them due to side effects and have just started the gluten-free (plus wheat and dairy free) diet a week ago so I'm not seeing results as of yet. Hopefully soon.
Have you been checked for Hypothyroidism? Ask for the full thyroid panel (T3 and T4), not just the TSH. Autoimmune Thyroiditis (Hashimotos) won't always show up on the standard TSH test.
Also, antidepressants have a lot of side effects. I'm not sure which medication you are taking, but here are side effects from Paxil: PAROXETINE (Paxil) Common: Nausea, vomiting, sedation, fatigue,
drymouth, headache. Occasional: Insomnia, agitation, tremor, diarrhea,
constipation, dizziness, sweating (a lot of the symptoms you are experiencing!!). You might want to Google "side effects" and the med you are taking and see if that could be your problem.
Hope you solve this soon! It sucks to feel like crap all the time.