Is it a bad sign if I have not felt the baby move by 5 months?

Yes. If you have felt no baby movement over the course of days or in your case months, you should contact your healthcare provider immediately in order to have an examination of the baby's heart rate and presence.
See below. Some mothers do not feel the child move until late into the pregnancy. Your OB doctor should be able to check fetal heart tones and movement. This can be done via ultrasound to get a really good idea of movement. Talk to your OB doctor to express your concerns.