Yesterday I had dinner with my colleague Isabel after work. We had planned to try some Chengdu food, but so many people were lined up in front of the restaurant that we just gave up. Instead, we had a barbecue and ate some ice cream afterwards. Although I was pretty tired coming home last night, I had a really good time. This was the first time I have hung out with a colleague after work. Since colleagues usually only see one another at work, I consider myself lucky that one of mine has now become a friend.
No mistakes. Good sentence structure.
Of the three choices:
1 - I really had a good time
2 - I had a really good time
3 - I really did have a good time
the one that shows the least enthusiasm is #1.
One possible thing you might work on is discovering more interesting verbs. This is not a mistake to correct. Rather, it is an opportunity to improve the breadth of your vocabulary. Your only verbs other than "have", "be", and "get" (the least interesting verbs in the language) are "plan", "try", "eat", "keep", "consider". That's not bad, but there's room for improvement. You could "dine" instead of "have dinner". Instead of having a barbecue, why not "enjoy" one? Instead of being tired, why not "nearly collapse". It sounds so much more interesting if you introduce some drama. Instead of keeping contact, why not "mingle": "people usually mingle with their colleagues only at work".