Formal:
* Je suis béni(e). (This is the most literal translation, and is appropriate for formal situations.)
Informal:
* Je suis chanceux(se). (This translates to "I am lucky" and is more common in everyday conversation.)
* J'ai de la chance. (This also means "I am lucky" and is very common.)
* J'ai beaucoup de chance. (This means "I am very lucky" and emphasizes the feeling of being fortunate.)
More poetic:
* Je suis comblé(e). (This means "I am fulfilled" and implies a sense of deep gratitude and contentment.)
Religious context:
* Je suis béni(e) par Dieu. (This means "I am blessed by God" and is used specifically in a religious context.)
The best option will depend on the context of your conversation.