According to Honda, the 2005 has a 20.4 gallon tank. According to my fill-up records, I get about 17.5 gallons into it if I fill up shortly after the light comes on, so yes, you should have 3 gallons +/- left when the light fist comes on -- or 45-60 miles, give or take.
Delayed onset muscle soreness. Delayed onset muscle soreness (DOMS), also called muscle fever, is the pain and stiffness felt in muscles several hours to days after unaccustomed or strenuous exercise. The soreness is felt most strongly 24 to 72 hours after the exercise. It is thought to be caused by eccentric (lengthening) exercise, which causes microtrauma to the muscle fibers.
Work out: This may be just a sign that you over did it. Fatigue after a workout is not uncommon. Take some anti-inflammatories, stretch well, and ice your legs. It may be that you hurt more tomorrow than you do today. As long as it is not getting worse, just watch it and decrease your workout intensity until you are back to baseline. Otherwise, see a doctor.