No it's absolutely not ok, but it does happen.

Either the questions/answers you've written have suddenly got a lot of attention and were received very badly by a large volume of users (highly unlikely, they're of good quality), or an individual is singling you out for whatever reason.

In cases as blatant as this the system will automatically reverse those downvotes at some point in the next 24 hours so there's no need to worry about it.

If for whatever reason that reversal doesn't happen, or you continue to get what you feel are unreasonable downvotes that the system isn't automatically reversing, let a moderator know via a flag and we'll see what can be done.