Throwing up and nausea, my mom had this trouble after her surgery and was mainly due to Gastritis. So check out if you are having gastritis symptoms first as it is the most common cause  I believe.

Hi dear this is the problem relating to abdominal problem produce high level Hydrochloric acid and carbon di oxide during digestion . i will tell solution for this problem from ayurveda . dont eat food with water, drink water before 15 minute you are a good weight but you have low weight you will drink water after 15 minute. avoid over chilly , masalas, fry items , tamarind, acidic taste etc. goto bed after food at least 30 minute.
do not drink yoghurt's, curd, with non vegetarian. do not drink yoghurt's, curd on night, control the use of Dal. beans, potato, use fresh food avoid refrigerated processed food . eat regular time basis dont miss you breakfast . and you will try these ayurvedic medicines.
1: 100gm liqurace(glyceria glabra) root powder+ 100gm poem granada fruit shells powder +dry amla100gm+ terminalia chebula100gm+terminalia bellerica dry powder 100gm ( hreed beda amla)mix all herbal powder and use 5 gm powder mix with boiled water and use 4 times a day before starting these medicines please clean your abdomen that is 25 gm sunnamakky leaf boiled minute in 250 ml water and use night bed time 100ml. morning two to four time go to toilet and drink milk after stop the loose motion use these medicines regularly about two months enjoy and forgot your early aging, hair fall, hair whitening reduce eye power pray to me and write a comment for me

i have been throwing up right after i eat and i dont have any nausea