3<font style="background-color: yellow;"> </font>day<strike><font style="background-color: yellow;">s</font></strike> holiday.

We had 3 days off in <font style="background-color: yellow;">a</font> row.
<font style="background-color: yellow;">On the</font> First day, We had a date with no kids. It is <strike><font style="background-color: yellow;">for</font></strike> the first time in quite long period! (I would write it like this: On the First Day, We had a date without kids for the first time in a long while.) 
<font style="background-color: yellow;">The</font> Second day, we went to a spa. There was a bath tub on the ground and we could enjoy mountain view with naked. I feel relaxed.

(Maybe: There was <em>an in-ground tub</em> or maybe <em>a tub</em> where we could bath naked and enjoy the mountain view.)
Today, we went to my husband's mom's house. We talked, <strike>drinked</strike> drank and ate a lot!
I think maybe during <strike>this </strike><font style="background-color: yellow;">these</font> 3 days I put on <strike>my</strike> weight...Because I know how much I ate....
Anyway we had <strike>so good days </strike><font style="background-color: yellow;">a <em>great time</em> or a <em>wonderful time</em></font>!!

Actually you can change the <em>so</em> to <em>such</em> and it would sound much better. "We had such good days" or "we had such a great time". use such to add emphasis.

三連休がありました。
一日目はこどもなしで夫婦でデートをしました。かなり久々です。
二日目は温泉に行きました。そこには露天風呂があり、裸で山の景色を楽しめました。癒されました。
今日は夫の実家に行きました。私たちはたくさん、しゃべって、飲んで、食べました。
この三日間で体重が増えたかも知れません。。。だってどれだけ食べたか自分で知っているから。。
それはさておき、よい日々を過ごせました！