If you're not on anything then you could try increase your Dopamine and Serotonin level yourself with 5HTP (it raises the serotonin levels just like SSRIs do.) To increase the Dopamine you can buy L-Tyrosine. Both are supplements you can buy from amazon or eBay or most health stores.

Don't take 5HTP is you're taking any SSRI or st. johns wart because they can interact with each other.