I hope further testing shows better results for your baby's heart. I would move forward with hiring a doula who may be able to provide some support for you while this current situation plays out. I have a friend who received similar news. Thankfully, all was well with the baby's heart. She went through months of ultrasound and significant stress though and ultimately went into preterm labor. Both of them are doing really well, but it was dramatic at the time.
From what I understand, ultrasound technology has become more precise and with that comes some uncertainty with what doctors are seeing, because it's new. They order more tests, say wait and see, and meanwhile parents worry sick. I believe that many of these cases turn out to be normal or normal variations. I hope this will be the case for your little one.
From seeing my friend overcome with stress, I think it's really important that you stay calm and centered as much as possible. Stay connected with your baby and talk to her about what you are feeling. Take a hypnobabies course for relaxation skills or practice yoga and deep meditation. Hire a doula skilled in high risk births who may offer information, advice, coping skills and comfort. Enjoy being pregnant and focus on what you can do and not what you can't. Nurture yourself and your baby throughout every day.
I hope you hear good news soon.