Does anyone else get very low before period due

We’ve been trying for 5 months now and each month I find myself getting very low the day before I am due. I think it is anxiety and it horrible when you want something so much. I’ve always been told it just takes one time to get pregnant and now I’m finding out that it’s not always that easy I find myself feeling very low. I’m starting to feel very isolated and I don’t know how to explain how I feel to my partner so he fully understands.