Help! Is this normal in early pregnancy?

Today I am 5 weeks and 6 days so far everything has been going smoothly except for today I had woken up from a nap with extreme cramping only on my right side and my undies covered in blood ! Since then the cramping has lightened up (but still continuing only on the right side) no more blood has shed since then but I'm wondering if I should worry?! Please help. - Alexa