speedsuit sizing

I have no idea where to post this. I recently bought a Nike running Speedsuit in Small. When I tried it on, I had to go through the armhole and it was a very tough battle getting the shoulder strap over my tiny head. ASre they normally sized according to wrestling singlets (based upon mass), or do they just run small? For what it's worth, I have a 35" chest, 34.5" hips and 29" waist, which all means I'm a small

Why don't you get in through the neck hole? Saves you a lot of stretch over the head.

That's because the neck hole doesn't fit over my thighs, let alone my hips, unfortunately. It feels like it could rip at any moment. It definitely doesn't help that my flexibility at atrocious