New to this

Me and my other half have been trying for a baby for 4 months. Im not worried about not being pregnant yet but I was after some advice. I came off the pill in August after being on it for a very long time & my periods are still adjusting to it. I’m now five days later than I should be and I was late last month so I’m just wondering if anyone else has had the same problem. I’ve taken two tests which are negative. Apologies for being a bit simple about this if I seek simple but I’ve not tried to get pregnant before.