Sometimes it feels like my heart skips a beat or palpitates. happens at rest or when walking. is this dangerous? if not what is it?

Depends on the: Source of the extra or skipped heartbeats, and how often they come. Most often, it comes from the atria, so they are not as dangerous as the ones that come from venticles. But you really need to find out, and the only way to determine the difference is with a cardiogram. Conduction abnormalities can result in cardiac arrest in rare instances. Get to a doctor, so you can figure this out.

Likely benign : Premature atrial or ventricular contractions but holter or event monitor would answer the question. Adequate hydration can also help decrease frequency.