twitching in my uterus ?

Hi all ! According to the app I'm 5 weeks. I have my first appointment on April 20. Very minimal symptoms. Sensitive breasts, some back pain ( but that's normal for me ) and exhaustion ( I've been passing out at 9pm when I used to go to bed at 12:30am.) But what I am feeling is  twitching ? I keep feeling this twitching feeling in my uterus, It feels like when you get Spasams on a random part of your body and it twitches , and sometimes it feels like bubbles are there. Has anyone else felt this?