Newcomer CD50! help please :)

I'm very new to the app so apologies in advance if I get any terminology wrong! 

Just looking for a bit of advice or people's stories of their own experiences.

I'm currently on CD50, my average cycle spans for 32-37 days. I've only had one other cycle that lasted this long which resulted in a period on CD56 back in January this year, which I think may have been due to medication I had the month prior. 

I took a test (cheap internet Amazon brand) over a week ago which was negative and another only three days ago, again it showed negative. 

I don't have any symptoms that I've noticed other than cramps every so often and uncomfortable backache on three occasions. I also had two dizzy vertigo type spells which I know could have been down to any number of things - but for the first time ever! I had some spotting yesterday. It's made me very confused and unsettled about thinking that this is still only a skipped period or a very late one.

My mum told me that when pregnant with me, no bfp showed up any any urine tests, they had to have blood tests, however I struggle to think that the technology now would be unable to pick it up for me when it seems to work for everyone else - is this just wishful thinking as I'm already so late into the cycle? 

Does anyone have any advice or had a similar experience?

Thanks!

E x