Hopefully the OP has gone to the hospital by now, but in case he survived and is reading this:
What you were experiencing likely wasn't respiratory depression but serotonin syndrome (hence the hot, painful feeling in your head). Tramadol simultaneously acts as an opioid and an antidepressant (SNRI-type, being structurally related to the antidepressant Effexor), and is thus liable to cause serotonin syndrome when taken in excessive amounts, which may manifest as a number of symptoms including raised blood pressure, high body temperature, delirium, and seizures (and yes, that is a life-threatening medical emergency).
This risk is compounded in people taking antidepressants which, in addition to causing higher baseline serotonin levels, inhibit the formation of Tramadol's stronger (as an opioid) metabolite, meaning the difference between a recreational dose and a seizure-inducing one becomes even smaller.