In The Jewish Study Bible the versification is different, 8:18-23. Don't trust any classification system. All of them will too soon lose the poetic soul of the experience written of as they divide, and divide again, a whole experience - dissection cannot find a soul.
Just before these words at hand (8:13-17), Jeremiah is informed of G*D's decision to put an end to the people - to harvest them (and not in a good way).
I like the translation of verse 18 in The Jewish Study Bible. They note the meaning is uncertain, which always give a bit of liberty.
"When in grief I would seek comfort,
My heart is sick within me."
Jeremiah has heard extremely bad news and is looking for an out and only finds tears available to him. And this is confirmed in verse 21:
"Because my people is shattered I am shattered;
I am dejected, seized by desolation."
There is no healing balm available to the poor - the poor in G*D but rich in various idols.
Only weeping is left.
The spiritually poor lose track of G*D and their own Self. This shows up in the way they deal with One Another, Neighbors, and Enemies. They are already in exile before they even know exile to be a vague, far-off possibility that they will not be able to avoid.
Well, Friends of Jeremiah, a dishonest spirit is as troublesome as dishonest wealth. They go together. Whichever comes first, the other is sure to follow. So, given where we are and the predictability of another exile for any nation claiming to be a city on a hill, a beacon, without actually doing the hard work necessary to have us simply be a neighboring city and to only be a steel against which another's flint is struck, it is time to weep.
We are harvesting the accumulation of dishonest wealth and dishonest spirit. This is worth weeping over as we are too far gone to reasonably shift gears. In fact the pace of a coming exile is increasing. Those with ears can hear it grinding and slouching forward. Be not surprised. Simply do the cleansing work of weeping that keeps clear a larger vision beyond this particular desolation and grief:
Peace and Joy abound
take all you need
and a little more
to pass around