Trying to get pregnant

Hello I have two kids, three(2018) and one(2020). After my one year old was born I got on birth control, which was a 6 year IUD implant and I met my fiancé in December and got it taken out in February because we wanted to have a baby around or after Christmas time. Sad to say I’m still not pregnant. When I got it taken out they told me that I could be pregnant within 8 weeks and nothing has happened. I’m not saying we have sex as often as some may think we need to but it is around my fertile peak. Some months we’ve had sex two weeks straight, right after my period and the fertile period. Still nothing. I’m losing hope. Now it’s September and the app says my period is supposed to start three days from now and it actually started today. This is the first time it’s ever been three days early and I don’t know what to think about it. Any advice?