Welcome to MS.
I am glad you have found this place of healing and support.
The abuses you have endured make things very confusing. You were betrayed by those so-called "friends." You were also betrayed by someone who was once part of your family, which classifies his actions as a form of incest. Then, being 16 during some of the abuse, leaves you with feelings that are similar to adult survivors of sexual abuse/ assault, even though you were legally and technically a child.
Confusion is more than an accurate description.
But, as Sam pointed out, there are well over 10,000 guys here who understand that confusion and will help you work through it, too.
You are definitely no longer alone.
There are several books you might find useful.
Abused Boys: The Neglected Victims of Sexual Abuse by Mic Hunter
Victims No Longer by Mike Lew
I am certain others will share titles they have found useful. You can find these titles, and others here at the bookstore
Take your time and look around. You do not want to trigger yourself by reading too many posts at one time.
At your own pace, read the boards and wander into chat. The lounge (chat) is open 24 hours a day though it isn't always populated.
We also have moderated chats called Healing Circles.
They meet on Sunday and Wednesday evenings at 9pm eastern time and one on Tuesday at 19:00 UTC (European and African time zone) which translates to 2 PM Eastern US time zone. The Healing Circle on Tuesdays is scheduled to resume in January.
Again, welcome to MS.