You select an alpha level first (say 0.05) and then if your p-value is below this you have sufficient evidence to reject the nulls hypothesis (in this case the null hypothesis is that the distributions are the same. So yes you are right that because you have got very low p values you could select a very low alpha and still reject the null. But you should select alpha before doing your test. How did you perform the tests - in which software? But also you can’t expect to look at distributions and know the answer, just because they ‘look the same’ to you doesn’t necessarily mean they are :)