Slow rising beta hcg levels?

Sin • 31 years old, mother of 2 beautiful girls, a handsome boy, and stepmom to a beautiful teenager. Married for 11 years
Im approximately 8 weeks pregnant and my levels went from 23000 to 25000 in 48 hours. I've had some light pink spotting and my obgyn has me scheduled for an ultrasound next Tuesday (a week from today,) Has anyone had such a slow rise and still had a viable pregnancy? I'm so worried!