Can somebody help please I'm losing my mind!

[Bikeracer2020]

From comments I've seen on this forum, Sketchup is a poor choice for producing STL files.

Plenty of free cad programs on the internet that work well for producing suitable printable files for 3D printing. Fusion 360 is very good but has perhaps a steeper learning curve than others.

Look on Youtube for the various programs available.

[Toasty]

Thank you for your reply.

I am aware Sketchup wasn't designed with 3D printing in mind, that said it does claim to be compatible. I've had a couple issues before, I just really like how Sketchup works, I've been using it since I was at school. However I will take your advise and have a look for alternatives.