You are vegetarian and almost vegan? This is my case and as I am living in Barcelona since a while I want to share with you some places I like to go or would like to go for good prices!
POBLENOU - Not too far from "forum "place" of the festival : Sopa - not open on the week end....
They opened https://thefoodassembly.com/ + yoga activities + healthy food!
https://www.tripadvisor.com/Restaurant_Review-g187497-d4985394-Reviews-Sopa-Barcelona_Catalonia.html
BARCELONETA - WOKI - Cheap good, in front of the beach! I go there every week end!
http://www.tribuwoki.com/restaurante/woki-playa-barceloneta/
GOTICO - Dionisios take away - the best greek falafel in the world and greek speciality! You have the resaurant and the small one to take away. Try the take away or eat in the small take away, nice staff, welcoming and good quality food.https://dionisosrestaurants.com/en/quick-greek-gotico/
GRACIA - Ugarit - Sirian restaurant you have a take away near also from the same brand. Humus etc you will love it!
RAVAL - Petit brot : Organic -Vegan - Raw! the must! Check schedules! I went one sunday it was closed :-(
https://www.facebook.com/petitbrot/
Here a guide for vegetarian restaurant if you want more options:
http://comerc.bcn.cat/sites/default/files/arxius/[PDF]%20Guia%20de%20Restaurants%20Vegetarians%20-%202a%20Edici%C3%B3_CAT_ESP_ENG.pdf
Happy Veggi life :-)
