Verified answer

Correct would be:

He tenido un día largo = I have had a long day (remember to put the adjective behind the object)

Tuve un día largo = I had a long day

I had = tuve

I had to go to class in the morning = Tuve que ir a clase por la mañana

I was tired = Estaba cansado (masc.) Estaba cansada (fem.)

Although it's easy to say 'He tenido un día largo' = I have had a long day and 'Tuve un día largo' = I had a long day, this is not strictly true. Spanish (in Spain, at least) uses the present perfect, i.e. the first phrase, to describe a completed action in the recent past - often the same day - and the pretirite, i.e. the second phrase, to describe a completed action that took place a little while ago - may even be yesterday. Much is in the thoughts of the speaker.

Tuve que + infinitive is 'I had to...'

YO HE TENIDO UN LARGO DÍA: when the day is not over yet.

TUVE UN LARGO DIA: when the day ends

first one says" i have had a long day"

second one says " i had a long day"

conjugate accordingly.

i had = yo tuve, tuve

i had to go to class in the morning = tuve que ir a clases en la mañana

i was tired = estaba cansado(a)

when talking about a personal experience, you usually have to drop the "I", or "yo" in spanish.