Headache Question - Sorry, I know there are tons!?

Question for those who suffer migraines. Friday AM i was clearing my throat and ended up gagging myself - i have a VERY SENSTIVE gag reflex - anyway - as it was AM and i had nothing in my stomach - i was retching pretty hard and just white foamy stuff came up - i'm uming the nasal drainage i was trying to clear. Anyway - when i stood up (i was hovering over my sink b/c i wasn't near the toilet when this happened) i had the worst headache i'd ever had - my face was bright red - i ume from all the blood rushing to it and my sinuses too - anywho - the headache lasted for about 5 minutes - i blew my nose about 5 times and each time it eased the pressure in my head. After the headache intensity subsided, i had this dull achy head all day - it went way Saturday but Sunday it was back but just in the back of my head on the left side - nothing helped it but lying down in the dark room. Today it's just dull - not sure if it's tension from retching or a migraine - anyone?