sigh no more ladies...

This is a lyric from movie "Much Ado About Nothing", originally written by Shakespeare :

Sigh no more, ladies, sigh nor more;
Men were deceivers ever;
One foot in sea and one on shore,
To one thing constant never;
Then sigh not so,
But let them go,
And be you blithe and bonny;
Converting all your sounds of woe
Into. Hey nonny, nonny.

Sing no more ditties, sing no more,
Or dumps so dull and heavy;
The fraud of men was ever so,
Since summer first was leavy.
Then sigh not so,
But let them go,
And be you blithe and bonny,
Converting all your sounds of woe
Into. Hey, nonny, nonny.


I wonder what's the definition of "dumps " in "Sing no more ditties, sing no more,
Or dumps so dull and heavy"; could it be some sort of song?