88' Mercedes Benz 560 sel won't start

Lately, since it has been getting colder, this car has done nothing but get worse. Not shocking, knowing that there is almost 200,000 miles on it. Anyways, lately it has been getting to where almost every night, after leaving my car sit for more than 5 hours, it wouldn't start. Id have to have my dad jump start it every night I went out. Well two days ago, I went to get in my car that hasn't been started all day and it completely wouldn't start at all. I was getting a noise but no juice. My starter and alternator are fine. I went to test my fuel pump relay and jumped it. That's fine. But when I go to slightly turn my key over you cant hear my fuel pump. So does this mean I need a completely new fuel pump?