I can help
Can you take a look at the following link and answer the questions at the bottom of the sheet? Your answers will allow me to accurately model the loading and size your beam. Thanks
Few more questions:
1. What is the span of your roof trusses (distance between the exterior walls)?
2. What city and state do you live in for possible snow load consideration?
3. Can you share a couple of pictures of your house so I can make sure I fully understand your configuration?
Let me know when you come back online