My Dads brother had kids with my Mums Mum (So my uncle got with my Grandmother on the opposite side) Does this somehow make me inbred? ?

If God allowed your family to remain intact, then the issue of inbred isn't an issue.  

i dont think so

no but damn that's awkward

No.  I don't know what your specific problem is, but it's not inbreeding.

Allow me to simply things so you aren't so confused.  Your Uncle had sex with your maternal Grandmother.  Who are the "they" who then had two more sons?  Your Uncle and your maternal Grandmother or two other "theys?"

No, your Uncle's children are your cousins, not your uncles.

"He" was never brought up as "her" uncle.  Who is "he" and who is "her?"

Why your uncles, your father's brothers, would call him "Dad" likewise confuses me.  Maybe they don't understand "brother."

I have an even better story, but mine is true.  Person I work with was married, had a child with her husband.  Divorce the husband and married HIS father.  She had a child with her second (considerably older) husband.  The grandfather of her first child is the father of her second.

Although your tall tale lacks any merit, it sounds like you should have chaperones at your family reunions.

No, only the children resulting from their encounters would be considered 'inbred'.