That would be the grammatical correct way to say it.

Capitalize Just.

Comma after know.

Eliminate have.

Capitalize Take.

Take care always is colloquial, but it works.

Revised = Hi! Just to let you know, I dreamt about you last night. Take care always.

“Hi! Just want to let you know that I dreamt about you last night. Take care!”

you grammar is basically all correct, just remember to capitalize all words that are in the beginning of the sentence.

Hi! Just wanted to let you know that I

(any of these three would be okay)

a) had a dream about you last night.

b) dreamt about you last night.

c) dreamed about you last night.

Take care!

Always yours,

your name goes here…

“(This note is) just to let you know that I dreamt about you last night. Take care always.”

You also have to omit the “have” in “have dreamt” because of the time reference making your verb simple past tense instead of present perfect.

try this maybe

hi! I just wanted to let you know that i had a dream about you last night. anyways take care

by the way i really had a dream about you last night 😉