You did it, you reached the finish line, broke a PR and maybe enjoyed a victorious brunch.  You probably went to bed thinking "I should feel fine tomorrow" but when that alarm went off this morning, the legs were not loving you.  DOMS, delayed onset muscle soreness can catch you by surprise and could hang around for awhile.  Foam rolling is a great wayhelp yourself deal with the pain. 
A study from the Journal of Athletic Training looked the the effectiveness of foam rolling to treat DOMS after power lifting as well as running.  To measure the results, they used pain threshold as well as a speed test and a dynamic lifting test.  They found a significant decrease in pain aswell as an increase in performance for the subjects that foam rolled. 
Obviously, the sooner you can get into physical therapy the better but the rest of the week but it's important to foam roll everyday.  When foam rolling, sit on the floor and turn on your favorite half hour show.  Spend 5 minutes on each section of your legs.  When you find a really tender point, stay on it for an extra minute.  The more soreness you can tolerate when you are foam rolling, the better your pain will be afterward. 
Pearcey, G.  Foam Rolling for Delayed-Onset Muscle Soreness & Recovery of Dynamic Performance Measures.  Journal of Athletic Training. 2015;50(1)5-13. 

Kathleen Leninger, DPT