A man who gets too happy when prosperity comes
trembles when it goes.

[Quem res plus nimio delectavere secundae,
mutatae quatient.]

Horace (65–8 BC) Roman poet, satirist, soldier, politician [Quintus Horatius Flaccus]

Epistles [Epistularum, Letters], Book 1, ep. 10 “To Aristius Fuscus,” l. 30ff (1.10.30-31) (20 BC) [tr. Fuchs (1977)]
    (Source)

(Source (Latin)). Other translations:

Who so was to much ravished and to much joy did take
In flow of wealth, him chaunge of flow yea to much shall yshake.
[tr. Drant (1567)]

Him, whom a prosp'rous State did too much please;
Chang'd, it will shake.
[tr. Fanshawe; ed. Brome (1666)]

Those whom the smiles of Fate too much delight,
Their sudden Frowns more shake and more affright.
[tr. Creech (1684)]

They who in Fortune's smiles too much delight,
Shall tremble when the goddess takes her flight.
[tr. Francis (1747)]

Who prizes fortune at too high a rate,
Will shrink with horror at an alter'd state.
[tr. Howes (1845)]

He who has been overjoyed by prosperity, will be shocked by a change of circumstances.
[tr. Smart/Buckley (1853)]

Take too much pleasure in good things, you'll feel
The shock of adverse fortune makes you reel.
[tr. Conington (1874)]

Whoe'er hath wildly wantoned in success.
Him will adversity the more depress.
[tr. Martin (1881)]

Him whom prosperity too much elates adversity will shake.
[tr. Elgood (1893)]

One whom Fortune's smiles have delighted overmuch, will reel under the shock of change.
[tr. Fairclough (Loeb) (1926)]

One overmuch elated with success
A change of fortune plunges in distress.
[tr. A. F. Murison (1931)]

One whom a favorable turn of events overjoys
A change for the worse undermines.
[tr. Palmer Bovie (1959)]

If Fortune’s been kind
-- Too kind! -- loss will seem more than loss, will seem
Catastrophe.
[tr. Raffel (1983)]

Change will upset the man who's always been lucky.
[tr. Ferry (2001)]

Those who are overjoyed when the breeze of luck is behind them
are wrecked when it changes.
[tr. Rudd (2005 ed.)]

Those who’ve been quick to enjoy a following wind,
Are wrecked when it veers.
[tr. Kline (2015)]