I'd liken it as a simple mood swing for you since you're only 22 and quite young. You probably feel down from getting that hernia or your lover is concerned for your health and you have too much on your mind.
I think you should be more focused on making a full recovery before making plans to jump into bed with your partner. It probably is a crash to see yourself at 22 and having an operation, it does take more time to heal from a hernia.
If you still continue it, I would look at your diet and see if it has changed a bit since your operation it may be an issue with not getting enough nutrition.
Don't feel bad ;o
I don't think we have many members in their 40s or 50s yet in order for you to get more responses though...