Any help can mean much, sort of depressed

Fell in love with a girl at work, but didn't tell her as I knew she doesn't approve of love ( typical indian mentality), because her parents wouldn't approve. She always used to tell she had nothing against love or being in relationship, but as her parents wouldn't approve she didn't want to be so, then to later on feel heartbroken. But I still loved her, I don't have reasons, but I love her so much..
Everyday was difficult, I knew if I told her, she would stop talking to me. Days passed, and somehow she knew I had feelings for her ( many of our friends knew it before itself, by observing the way I was with her) and it was kind of late that she guessed I had feelings for her, so gradually she started maintaining distance with me, I kept asking her the reason even though I knew.
Then the silence grew much, I was feeling so depressed at times, knowing that I love this girl, but couldn't talk to her, that tore me up so much.., so one day I took up the courage to tell her I love her, and I did, she said she didn't wanted to talk much, I said I understood her,. But still as I tried to not disturb her, my depression grew, my friends were there for me to share what I thought, which was a relief .
And weeks later I wrote her a letter, remembering all the wonderful memories I had with her, how I fell for her, and finally wrote that I wished her to be happy, even if her future didn't have my presence with her, and told her no matter what happened I would always wait for her and always love her,..

I thought my coming days would be manageable, but it's harder than I thought, ofcourse I spend time with my parents, siblings, and friends, but her absence is a torment for me, I sometimes think of texting her, but I never wanted to disturb her if she doesn't want to be with me.. I leave office soon.. gonna fly abroad to study,.. any advice or ideas or suggestion are welcome..