3 Positive HPT, negative blood :(?

my period is nearly two months late ? I took 3 positive home tests and just got the news that my blood work came back negative? I have a follow up appointment for an ultrasound to see what's going on in a couple days but im getting irritated. Has this happened to any of you? I'm just 22 and so is my boyfriend. I told him the second I got a positive test (a month ago?)! I waited to schedule an appointment because articles online have been telling me that seeing an OBGYN before 12 weeks is dumb because they don't even really see much on the sonograms until then unless you want the pregnancy confirmed. And I thought THREE positive tests would be enough confirmation that I am DEFINITELY pregnant. I live far from home and haven't found the time to tell my family about the positives and decided I would wait for sonogram pictures, but the negative blood work is disheartening. I told my boyfriend the second I got a positive test and it's been really difficult for him to process but I think he's okay now. I will be very disappointed if I am not pregnant. Could something else be wrong with me? Could I be producing the pregnancy hormone without actually have conceived? Is blood work ever inaccurate? How am I going to tell my boyfriend if I end up not being pregnant? :( Any advice will be beneficial, thank you.