Without reading anymore than your original post.
Major depression
Plan
moodtracker.com
Get an account.
Initially realign your sleep patterns use some melatonin, set sleeping hours and introduce some excercise and yes red lentils to your diet.
Check for bipolarity in your history i.e. any incidene of being high spending a lot and perhaps having a lot of sex, over productive periods along with grandiosity, flight of ideas and tangential thought.
Check family history
Moving on:
Pill called an antidepressants, usually an SSRI or SNRI (easy to look them up) I dont do drug companies names or products.
See your General Practitioner have he or she assess the issue. Be careful if you've been elevated in mood before, bipolarity as described above can render you suseptable to further dangerous highs if you use antidepressants without a mood stabiliser combination therapy !
Here is a link worth it
http://www.blackdoginstitute.org.au/
( Edit)Read back and missed the "extreme thirst" this is called polydipsia, do you have excessive urination this is called polyuria?
Both are symptoms of other medical issues that range from diabetes to many other disorders . These will need to be excluded before progressing to any depression treatment. Simply I've seen people with major thyroid issues presenting as anxious and all over the shop and once fixed back on track.
Quite clearly you need to see a doctor and not avoid it.
Hoping this helped