The most common and most likely answer to this crossword clue is the 10 letter word OVERLOADED
I've seen this crossword clue in The Daily Telegraph
O
V
E
R
L
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A
D
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D
More clues leading to the result OVERLOADED
Buddy explains!

The straight part
We know that "Carrying too much" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case carrying too much = overloaded.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does OVERLOADED mean?
OVERLOADED verb- To load excessively
- To provide too much power to a circuit
- To create different functions for the same name, to be used in different contexts
- To fail due to excessive load
- Loaded too heavily
- Of a word, having multiple meanings depending on context
- Of a name, used for more than one variable or procedure etc; differentiated by the compiler based on context