There are several factors that could result in you not being able to access your Facebook account. One of those reasons is that your service provider at that moment could be bad and not able to open the facebook site.
Another thing is that you might have shared stuff that goes against the Facebook community standard and as such may result in your account being blocked.
We could go on and on...However, let's assume that your account was disabled by Facebook due to reasons best known to them.
And if that is that case here, how do you get back into your account?
Well, if Facebook should block your account, all you need do is to contact the Facebook team directly by filling an appeal form.
In that form, you should be able to state clearly the reasons why you think your account was blocked and why they should unblock it for you.
I bet you if you can do that, your account will be unblocked immediately.
Just try that tips and see what happens in the next minutes.