What term describes the feeling of routine sacrifice or loss of opportunity due to a conflicting obligation?

Solution 1:

I believe you are looking for self-abnegation or abnegation.

self-abnegation: the denial of one's own interests in favour of the interests of others Collins

Here are some more details and an example from vocabulary.com:

The noun abnegation definitely has the sense of self-denial and self-sacrifice. So you wouldn't use abnegation to refer to the fact that you are giving up candy in order to eat more fruit. Instead, you would use the word if you were giving up desserts in order to donate to charity all the money you saved by not eating them for a month or two.

Solution 2:

Sounds like you're balancing guilt vs regret.

Google's first definition of regret currently is:

a feeling of sadness, repentance, or disappointment over something that has happened or been done.