Can i be pregnant? Help! Early signs and symptoms and follic acid

Hi, I'm new to this forum, i joined to get a better understanding and advice on my trip to conception...
My hubby and I have decided to try for our first child, we have been tracking my fertility and ovulation periods via an app for the last 3.5 weeks.
I started getting signs about 4 days after ovulation. I started to feel tired, lost my apetite, then randomly started craving. I was getting discharge but i didnt want to get my hopes up thinking it could be that i may be in implantation...
I knew it was too early but I took tests anyways and they all came out negative.
4 days ago I went to my dr to get some advice and she got me started on elevit folic acid tablets.
It is my 3rd day since ive started the folic acid tablets, im feeling nauseous and have this soapy like taste in my mouth.
I have also realised my boobs have grown but more so rounded up and were quite tender.
It is the 19th of August today and im due for me period on the 24th. My period is verrry spot on. I get in on the 24th every month which lasts about 5 days.
Ever since ive been on the folic acid i feel more tired as well as nauseous. Has this happened to anyone else??
My signs and symptoms could also be the signs before my period...
But what makes me think is the amount of discharge i have been gettting... i usually dont have much untill im reaching my ovulation period.
And its not the cottage cheese sought either where i can say nahh its an infection.
Its white and quite creamy.
Im very eager to go down to the chemist and buy every pregnancy test there is on the shelf... but i dont want to kid myself either.
How did you know you were pregnant before your missed period? What other signs should i look for?