Advice please..

The usual post that millions people probably write on a day to day basis but it's my turn now..

It's my 3rd day being late on my period but Starting yesterday and today I have been get light brown discharge. Is this a sign of my period coming or implantation bleeding.. I have been trying for over a year now and every month is a disappointment so hoping this might be my month but having doubts.

What should I do wait it out until it's a week without a period or take a test tomorrow morning? Just been hard for me and my partner even tho he has 5 children from his previous relationship. Grateful for them all and love being their step mum but just wouldn't mind my own little one to join the family and later on instead of hearing my name from a child it will say mummy.

Any help or advice would be great.

Thanks in advance