Even though the reasons are valid in your head, i.e., bad health, transportation, taking care of family members, you have guilt. Someone taught you a lesson that school is the way you need to get ahead in the world. The guilt might subside if you talk with your teachers/counselors, and explain your absence. Ask if you can do something extra to make sure your grades stay up and you're taking advantage of the education. Good luck in your endeavors!
Even though you miss for good reasons, it is a good sign that you feel bad. That shows sign of taking responsibility. Be careful though, even with good reason, if you miss too much time you can be held back. No matter how good your grades are you can't pass if you miss too many days.
Yea Im off today for a good reason too. I feel a bit guilty too because of the stuff I'm missing out on, and what I will have to make up. Who knows what my friends are talking about or what crazy things they're doing without me! Plus, ya gotta live your life! Your life shouldn't just be about school! :P