Adidas Sleek - Size help

[rk47]

I'm a size 4.5-5 and saw that you should size up in Sleeks so ordered a 5.5. They were too small so exchanged for a 6. Not sure if they're too small - I think they'd be ok if they give a bit but not sure if I should order a 6.5 or if they'll be too big. Seems crazy! I really like adidas but find their sizing a nightmare.

Does anyone have any advice on sizing or if they give at all with wearing?

I am a 7.5 in Nike but had to get an 8 for my sleeks, they are fine length wise but pretty snug width wise... I think I could have gone 8.5!

Thank you both.
Maybe I have weird feet! I ordered the 6.5 too and they might be too big at the back. Really like them but can’t decide between sizes.

I'm usually a 4.5 - ordered the 5 and too small. Got the 5.5 and ok lengthwise but just ok width wise. I'm persevering with these as I really like them.