Feeling really down only 7 weeks and something

Is it okay to feel really down? I keep crying and overthinking everything. Ive been overthinking me and my boyfriend and second guessing everything. He has a son with his ex who’s only 9 months old. We were together in the past and separated for 2 years and then got back together now when his son was only 5 months. They had separated… and I’m overthinking if it’s truly meant to be and if I made the right decision because I keep thinking if they get back together and then I stay alone. I love him and his son and I guess it’s just my hormones and the whole new co-parenting.