Congratulations on your graduation!
I would translate it along these lines:
During the reign of the most venerable
Carl XVI Gustav
king of Swedes,
our merciful lord,
by the order of the faculty of science at Uppsala
[name of conferrer of degree]
doctor and professor,
legitimately in the office of a promotor,
make this man who is brilliant in the fame of his wisdom and the grace of his ways,
a doctor of technology
decorated and improved by all the rights, titles, and privileges
by which this degree in technology is traditionally distinguished
made known with this diploma
by the seal of the order of philosophers and my name.
This is close to what the formula looks like at my university; see this old question.
My translation takes some freedoms, as the ceremonial structure is a bit odd.
Everything after the first line is a single sentence whose subject is ego, predicate is facto, and object is virum.
The first four lines after "D D" are an absolute ablative and all the ablatives refer to the king.
This is similar in spirit to Roman consular dating.
The core of these lines is imperante Carolo, and the rest can be seen as decoration.
The fifth line has an unrelated ablative iussu, "by the order".
The abbreviation "D D" is probably short for de dato, meaning that the document is dated to a specific date.
This abbreviation appears to be in use in Sweden where the university in question is.
The position at the top of the page suggests something formulaic like this, and it is unlikely to mean much.
It could in principle stand for Divinitatis Doctor if that is what you got your doctorate in, but the name of the degree should come much later in the formula.
Without seeing the diploma it is hard to judge how much weight "D D" bears, but it seems to be syntactically disconnected from the rest of the text.