Some good advice mixed in above. My advice would be to get a second opinion on your fit, to make sure it's correct.
If the fit is correct then your friends are right, you need to get used to the position and swapping out stems isn't going to help. But what may help in the meantime is raising the bars for some time.
I have an old fashioned quill type stem and after the snow melts each year I raise it up a good centimeter or two. Then after a couple weeks breaking myself back in to riding the bike again, I drop it back down.
P.S. Shortening the stem also changes handling and you may not like the twitchier, less stable feel it brings.
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If once a man indulges himself in murder, very soon he comes to think little of robbing; and from robbing he comes next to drinking and Sabbath-breaking, and from that to incivility and procrastination.
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