Im 5 weeks pregnant got ultrasound doctor says he only see gestational sac with tissue inside got bloodwork done my hcg about 300 is something wrong?

May be too early: It may be too early still depending if you're really 5 weeks pregnant. Sometimes your cycle may be off and you may be earlier than you think. I'm sure your physician has a follow up appointment scheduled with another blood HCG draw and possible ultrasound in the next week or so. Give it a little more time. Wishing you the best!

Maybe : 5 weeks is very early and everything could be just fine or this could be a blighted ovum. A repeat quantitative HCG should be done in 2-3 days and will tell you more. It definitely is not time to give up hope. Hope this helps and all is well.