I was on 10 mg of citalopram and i upped my dose to 15 mg and now i feel horribly depressed again. advice?

Medications require: Careful monitoring/adjustment by prescriber. Take only as prescribed. Discuss effects & symptoms with prescriber who will guide dosing or consider additional/alternative interventions/therapy. It is possible that 10mg is better than nothing but 15 mg is too much. Consider life situations that may be contributing to depression & address them. Work on healthy living habits. Hope you feel better soon.