Reassurance please

11 weeks & 5 days here. Was at doctor apt and couldn’t find babies heartbeat on Doppler. (Not my first baby and I’m pretty slender) After different doctors trying they said they “think” they picked it up for a second. Not reassuring what so ever, but they acted totally calm and saying “they know a baby is in there”.... I understand they don’t want me to panic and have me scheduled for 4 weeks from now but I’m really nervous now. If any of you had similar experiences please do tell any advice would be wonderful as well. Thanks in advance 💕

UPDATE :

I called office and mentioned it was bothering me and I’m suppose to receive a call back. Thank you all for the input! ☺️