Still Spotting :(

Im 5+2 today. I've been spotting very small amounts of pink and red for over a week now. Doctor did an ultrasound at 4+4 but it was so early they couldn't even see a sac. They couldn't see any obvious sources of the bleeding either. my spotting comes and goes and can only be seen when I wipe. Doctor told me to call him back when I reached 6 weeks and he would order me a 7 week ultrasound. This is my rainbow baby :(. I'm praying that I dont lose this little one too :(. Anyone go through something similar and have everything turn out okay?