Hi Chris. In native english speaking, we usually shorten it from " i have had" to"I've had". *Have had* has 2 meanings: 1) You owned something in the past -example: " I have had 3 phones." 2) You experienced something in the past -example: "I have had better days. " or it can be continuing from the past into the present. -For example: " I have had this book since December 2019. "

Thank you everyone spend ur time answer my questions

What the difference if i change to I am a bit sad to go back to work, but at least I have a nice time off with my family

I have had so many ups and downs in life.

It's the present perfect tense. You could say "I have had many good meals in that restaurant" for example.