Gloomy town dead picking up with second amount of energy injected (9)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

CITY (large town) + D (abbreviation for dead), reversed (picking up = upwards in a down clue), with S (abbreviation for second) + PEP (a dose of energy, as in “pep up” or “pep talk”) inserted (injected). Dyspeptic = suffering from indigestion, but the word is also used figuratively for being gloomy or irritable.