Your sentences make sense, but if you'd like it to sound more native or flow better, maybe you could try this instead -----v "I was going to go out with some friends, but didn't in the end. I had to catch up on some sleep and was in bed by 10:30." Using 'though' would mean you made a conflicting statement before this one, which you didn't. Also, shorter sentences can be combined with the one before it by using a conjuction (a connector word) to keep from repeating the subject so often (I, he, she).

It's fine, although I would drop the "though". It generally marks another statement as contrasting with the first, whereas going to bed early is very consistent with not going out. You might use the word if you had in fact chosen to go out.

The previous two answers are both good. You also forgot to add the word "to"... I had TO catch up...

I would prefer "but, in the end, I didn't". Insert a "to" before "catch" and drop the "though". Time is written with a colon, not a decimal point(10:30, not 10.30). There is no need for an exclamation mark(!). ----- I'm not looking for downvotes on this one, thanks.