There are many reasons why your eardrum may seem as though it is beating, constantly. This means you could have an infection, sustained an injury or any one of several other problems.
Most importantly, your concern can be a serious or non-serious matter. Only a physician is equipped to answer your question definitively. There are Ear, Nose and Throat Specialists who examine and diagnose ear problems. No one can tell you, if you are losing your hearing, except a Physician or an Audiologist, specializing in hearing loss. Although, you may be experiencing an apparent loss of hearing at this time. Your concern is legitimate and probably very irritating to live with as any similar condition would be.
I encourage you to see your family physician soon, or schedule an appointment with a Specialist, to prevent any future loss of hearing.