I have made a promise to Allah but now I feel that I cannot fulfill my promise or commitment. Is there a penance for this situation?

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

Breaking promises is among the characteristics of hypocrites. The Prophet (Sallallahu Alaihi wa Sallam) said: "Whenever he (hypocrite) makes a promise, he breaks it" . [Reported by Imams al-Bukhari and Muslim ].
Generally, fulfilling a promise is among the good qualities and virtues. Allah reported about the Prophet Ismael (Alaihi al-Salaam). Allah Says (interpretation of meaning): {…Verily! He was true to what he promised, …} [19:54].
Whether fulfilling one's promise is obligatory or not is a disputable matter among scholars.
The majority of Muslim scholars believe that it is desirable without any condition.
Malikiyah are of the opinion that if breaking a promise causes any harm to the promisee then fulfilling such a promise becomes obligatory.
Some other scholars believe that under any circumstances the promise should be fulfilled.
Finally, if one has promised Allah to perform an obligatory act or to avoid a forbidden matter, then he should fulfill his promise; certainly such a promise has more right to be fulfilled. However, there is no expiation in breaking a promise.
Allah knows best.