You have some good tactics, you're looking ahead pretty far, and it looks like you know at least the first few moves of your openings. All good.
I was thinking the less ambitious 7...Be7 would have been better (then 8. Nxc6 dxc6 9. Qxd8+ Bxd8 10. e5 Nd7 might hold the position, although 11. e6 still has to be considered). My guess is that you made an opening error even before that 7th move since your position was weaker than it should have been at that point. That isolated, unadvanced "d" pawn looks like it's messing up your position. This is one of those Sicilian lines I don't know, so you'd have to look up the book moves for that.
What about 18...Ba6, which simultaneously threatens the queen and mate-in-one?
absolutely loved this game. I lost and pushed a bit too hard. I thought I had a combination but my calculation was off. What do you think of this game?
I inserted some of my calculation so you have sense ofwhat I was thinking. Where did I go wrong? Should my main focus be on calculation training? Because I made some calculation errors. I played some weird moves, but I thought they were good. Went for the attack and seized the initiative because my opponent hadn't castled yet. All in all a funny game and hope you can help me out! cheers from holland.