Bonjour Eleanor,
Chris is correct! You can have Le Passé Composé followed by Le Futur Proche - See the example below:
J'ai trop mangé ! Maintenant, je vais devoir m'allonger = I ate too much. And now, I am going to have to lie down
You can have Le Présent followed by Le Futur Proche:
Aujourd'hui je suis très occupé parce que je vais faire des courses et je vais faire le ménage dans toute la maison = Today I am very busy because I am going to go food shopping and I am going to clean in the whole house
Attention: je suis occupé -> occupé = a past participle used as an adjective - it is not in Le Passé Composé
If you want to say 'you were busy' and explain what you did next, then you will have L'Imparfait followed by Le Passé Composé:
Hier, j'étais très occupé et je suis sorti pour acheter du pain = Yesterday, I was very busy and I went out to buy bread
I hope this is helpful.
Bonne journée !