I've a significant challengm going through a really hard time right now.

Grammatically correct, but "I'm going through a very/really hard time right now" sounds more natural.

Since my last post, I was forced to leave my house and go north with my family.

We had fun whenwere having fun until the sudden news stunned everyone ion the trip.

I'm absolutely terrified ofat the perospective of returning to home.

I've a signm going through a difficant challengult time right now.

"I've a significant challenge right now" sounds awkward. We typically don't say "have a challenge". "Going through a difficult time" is a bit more natural.

We had fun when thewere having fun until sudden news stunned everyone ion the trip.

Because the news was the reason why you stopped having fun, "until" illustrates that a little better. "when" would still work, but "until" feels stronger.

There awere bad events near our house.

I'm guessing you're implying that the bad events are still occurring now, but because you're describing the moment you discovered the bad news, you want to use past tense here, because the discovery was in the past.

I'm absolutely terrified of the perospective of returning to home.

Alternatively: "I'm absolutely terrified of returning home." is also fine, and more likely what you would say in conversation. "the prospect of returning home" is correct, but sounds a bit formal.

I've a significant challenge right now.

“I’ve” is controversial here.

Since my last post, I was forced to leave my house and go north with my family.

We hadwere having fun when the sudden news stunned everyone ion the trip.

There awere bad events near our house.

I'm absolutely terrified of the perospective (?) of returning to home.