From a reader…
I am struggling with food and alcohol addiction. After confessing this, my penance was to fast the next day after such indulgences. I was discouraged. My confessor did not know my circumstances. I have successfully done “fast'” and abstained from alcohol more times than before, but I feel horrible about my failures. I need more help than this guild of failure. I feel this priest does not understand. I do need forgiveness and grace, but not this sense of hopelessness.
First, good for you for recognizing that you have a problem to confront. Find all the help you need from others in order to map out your strategy and continue to ask God for help. I do mean all the help you need, which probably involves professional counseling and might involve support groups.
Be ready to suffer! You can do it.
Next, penitents are not obliged to accept every penance that the confessor suggests. There are, indeed, circumstances that the confessor may not know (e.g., telling you to find someone and make amends when there is not way for you to find that person, or there is no prudent or realistic way to have that conversation). Also, the confessor might suggest something that is not able to be accomplished in a reasonable period of time (e.g., say 10 Rosary a day for the next four months). Moreover, the confessor could give you something that is so vague that you have no idea of when you have done it (e.g., think nice thoughts about someone today). We are not obliged to accept such penances and we can ask for another.
Furthermore, I have written before about the matter of validity of absolution even if you do not do the penance assigned during confession. HERE.
It is clear in the Latin Church’s law that the confessor is to give penances. If he doesn’t give one, the absolution is still valid.
We are obliged to do penance for sins that we have committed. This is a matter of justice.
That said, the imposition of a penance is not required for validity of the absolution. In normal circumstances it should not be omitted. I can envisage situations when I as confessor would not give a penance, as when I am absolving an injured teen in an overturned car while the emergency teams are cutting it up with the saw to get him out. (I didn’t give a penance, but the absolution is valid.) Another moment might be when I have, with some difficulty, heard the confession of native Hmong speaker having only a few words in English or French, with no translator or even book to point to. Rather than make the situation an ordeal, I might just be confident in the penitent’s sincerity, absolve, and send the frustrated fellow on his way, satisfied that the confession itself was a penance.
You, as a penitent, can ask for a clearly defined penance, achievable in a reasonable period of time without undue burdens. You are not required to take whatever the priest suggests, particularly if by attempting to fulfill it, you might do yourself or others harm.
Finally, don’t be discouraged. God works wondrous things through fragile and erring priests: you obtained absolution for your sins! Now, be of good cheer. Even though you have a long road ahead, you are pointed in the right direction.