If it's a long weekend (including Saturday and Sunday),
you can say "three-day weekend."
If not, you can use the other two options.
I have a three-day weekend starting tomorrow.
明日から[3連休](https://eikaiwa.dmm.com/uknow/questions/5553/)です（土日含め）
I have a three-day holiday starting tomorrow.
明日から3連休です
I have three days off starting tomorrow.
明日から3連休です
長い[週末](https://eikaiwa.dmm.com/uknow/questions/41287/)（土日を含め）だったら、
three-day weekend
と言うことができます。
週末でなければ、そのほかの２つの表現を使っていただけます。
day off は「休みの日」という意味の英語表現です。
You can use the following sentences to express yourself:
I have a three day holiday starting tomorrow.
My three day holiday starts tomorrow.
表現する際に以下の表現が使えます。
I have a three day holiday starting tomorrow.
[明日](https://eikaiwa.dmm.com/uknow/questions/36265/)から[3連休](https://eikaiwa.dmm.com/uknow/questions/5553/)です。
My three day holiday starts tomorrow.
3連休が明日から始まります。
Well, really you have given a perfect way of saying that within your question and it's rather a challenge to improve on that!
You could say, "From tomorrow, we're off for three days." It is not necessary to say 'consecutive' in this construction as it would be assumed the days are consecutive unless you say otherwise.
If they are not consecutive days you could say something like, for example:
"We have three days off during next month but they are not consecutive days," or, "...one day is in the first week, one day is in the second week, and one day is in the thitrd week of the month."
A) I am off for 3 day's
*Off-absent; away from work.
Example-"take a day off"
B) I have leave for 3 days
*Leave -time when one has permission to be absent from work or from duty in the armed forces.
Example-"Joe was home on leave"
I hope this helps :-)
A) I am off for 3 day's
3連休なんだ。
Off
休み、仕事がないこと。
例-take a day off
（休暇を取る）。
B) I have leave for 3 days
3日間休みます。
Leave -
仕事や国防軍の軍役を休む許可を得た期間。
例-Joe was home on leave
ジョーは休暇で自宅にいた。
お役に立てば幸いです。
I have a short three day holiday that starts tomorrow.
>I am off for the next three days.
*By saying you are off is indicating that you have holiday.
"the next three days"are indicating that it is for 3 days from "tomorrow"
.......................
>I have a short three day holiday that starts tomorrow.
*This means that you have a three day vacation from tomorrow
.......................
I am off for the next three days.
3連休です
you are offと言うことで、休暇中だということを示しています。
the next three daysは明日から3日間ということです。
I have a short three day holiday that starts tomorrow.
明日から短い3連休なんだ
このことは明日から3日間休暇だという意味です。
We can use these three phrases with changing the words around to mean the same thing.
A three day weekend/holiday would explain that you have an extra day over the weekend and more time to relax.
We can also explain that it's a long weekend, meaning that we have a Friday or Monday off of work to make the weekend longer.
アメリカ合衆国 
南アフリカ 
イギリス 
