22 Weeks Cramping and Spotting

Hi I'm 22 weeks pregnant with our previous bay boy. I started having tight cramps in my lower abdomen this morning. Then after my husband and I had intercourse this afternoon I noticed a light spotting of blood when I wiped. Now I've been cramping all day and having sharp pains in my lower abdomen and lower back. Is this something I need to be concerned about? Should I go to the doctor ?