It can be hormonal changes. Only you will be able to know why you are having anxiety, it can be as simple as dark places, dim places, noises, overthinking etc. You need to speak this with gynae/doctor. In NUH previously I had, they ask for QNA pertaining health and mental. And during check doctor will ask you about anything. Having said that, speak with your spouse too. Dont keep within your self. Before bed time put some nice smell relaxing diffuser and listen to soft jazz music to calm yourself down
Hihii im in the same boat as you, had anxiety issues growing up too and this new journey brings my anxiety to a totally new level. For me, it helps to open up to my husband and loved ones (speaking to my mum helps too). Also I always prepare a list of questions for the gynae to help allay any fears I have. Know that we're not alone in this journey :)