Intense longing and grief

during school i got this extremely caring teacher but i could never speak to him or go to him due to social anxiety and selective mutism and i despite graduating from school by two years now ,i still feels regret-type grief for that teacher and along with longing even now so much so that i sometimes pray to god to make me meet him,i scan streets all the way when outside then return disappointed when i don't meet him,then wish again and return disappointed again....he'd pop into my mind triggerless 24/7 regardless of my day or mood....i tried many techniques and exercises like unsent letters, logic, visualisation, etc but nothing helped at all

[My background-:My mother left me when i was 3½ to my grandparents..... i used to cry as a 5 year old when my grandad would drop me to the kindergarten every morning really too much...so much that the even the teachers would need to tell my grandad to leave....i was like that every morning for months.....long after other kids had stopped crying ....even in grade I'd get late everyday for school as I'd not get up from bed just keep Lying beside my grandad pleading just 2 more minutes then he'd lovingly say now get up but I'd say another 2 minutes resulting in getting late .

You know since my first day at kindergarten only i was almost completely silent which followed me through the very last day of school even....You know when i was 5 whenever my grandparents would take me the shops to buy chocolates,candies,etc. I'd never buy them even when i wanted to,even the shopkeeper would say surprisingly that he's never seen any kid like this, i would think that i must not waste my granddad's money…… I know you won't believe it,but i really thought i shall not waste his hard earned money....not knowing at that age he'd enough money....When in grade 1 he'd drop me to school or pick me back by his scooter ....on the whole way I'd worry about him hurting his legs silently, I'd watch his foot throughout the street,my grandad passed away when i was 10 then my mother returned on the next day of his passing with my younger siblings,during school i got this extremely caring teacher but i could never speak to him or go to him due to my difficulties with social interactions and i despite graduating from school by two years now ,i still feels regret-type grief for that teacher and along with longing even now so much so that i sometimes pray to god to make me meet him,i scan streets all the way when outside then return disappointed when i don't meet him,then wish again and return disappointed again.When i look deeper i feel Even if i said, thank you and sorry the longing would still remain, I just feel like," I want to see me just like used to during school"[COMMENTS AND SUGGESTIONS TO GET BETTWR ARE DEEPLY WELCOMED PARTICULARLY WHEN NOTHING I DO HELPS]