I had low betas with my first IVF. It was a horrible roller coaster of emotions. At 7dp5dt it was 12, four days later it was 56, a week later 379, two days later 619, five days later 1914. It would rise just enough to keep up hope, but I ended up miscarrying a week after my last beta draw at 7w2d pregnant.
Miracles happen, but in my case low betas meant a non viable pregnancy. I hope you have a better experience. GL.