Stressed and feel pressurised. Alone.

I have been an introvert all my life , also i feel whomever i get attached to will leave me one way or other, therefore i keep to myself. My only constant source of love and security was my mother, she passed away last year . I find temporary comfort watching movies or reading books. Ive decided to focus on my career therefore working hard enough on exams. Amongst all of this my father is hell bent on getting me married. I know i cant handle a family situation or relationship that needs my efforts being put in. I've tried my best talking to him that im not ready for marriage. He says im being silly and acting underage, that im no child to make these excuses. And all my friends and cousins getting married who are around my age. I can't think of any way to get myself out of this situation. I'm getting over anxious about marriage and me facing unknown situations alone.