4 days late and bfn

Hi guys this is my first post.

So I’m 4 days late and have done a test each day and all have came back negative. I did the clear blue test which had the faintest line ever or maybe I was just hoping that’s what I could see. Since then I’ve done 2 digital tests which say not pregnant.

We have been ttc for around 8 months now with no luck and normally my cycle is pretty accurate according to this app.

I started taking folic acid supplements and pregnancy vitamins around 4 weeks ago so I’m not sure if this has anything to do with me being late? I had all the normal symptoms I get around ovulation and af time but nothing.

Can anyone give me advice please?.