Usually, for adult nonsmokers, the normal CEA levels range from 0 to 2.5 mcg/l. For adult smokers, the levels are slightly higher, and normal levels range from 0 to 5.0 mcg/l.
Generally CEA would be higher in patients with colon cancer. After surgery, the value would decrease, and the increase of CEA would raise the possibility of cancer recurrence. Your level of 7.5 is higher than normal, but if it is lower than the value before surgery, then it would be totally normal.