Green’s Dictionary of Slang

(US) delirium tremens, nervousness.

[1955		L.F. Engler ‘Gloss. Air Force Sl.’ in AS XXX:2 116: CLANK UP; GET THE CLANKS, v.phr. Become nervous].
1980		A. Pearl Dict. of Popular Sl.
2005		J. Dobbertin Window at St Catherine’s [ebook] Looks like you've got the clanks,” Walker said. “What in the hell are the clanks?” Bill asked. “Well, when you're in a tight situation you keep your nerves all bundled up.