Positive blood test now negative urine test. Help/opinions!!!

Lori

Okay I was supposed to start my period on Saturday 10/21, I took two pregnancy tests on Sunday 10/22 and got both faint positives, since I had never used that brand before, I wasn't sure if they were right so on Monday 10/23 I went and bought the first response since that's what I used with my other 2 kids and got another faint positive. Tuesday I started bleeding a little bit and called the doctor and went in and took a blood test. I never had any pain what so ever and the bleeding was much less than a period, it started out bright red mixed with some brown. It continued to be bright red mixed with brown until Wednesday evening, when it turned just brown and the amount of blood went way down to basically just when I wiped, still no pain whatsoever and I never had any blood clots. Thursday 10/26 the doctors office called me with the results and the hcg levels showed I was between 3-5 weeks and they told me to come back in on Monday 10/30 and I asked them about the bleeding and she told me sometimes your body doesn't know you're pregnant so it gives you a period and not to worry too much because that's probably all it as since I've had literally no cramps or anything and there hasn't been a lot of blood. She said usually if there's excessive amount of blood and pain that's when I should be worried. On Friday 10/27 I took 2 pregnancy tests and they both came up negative, so I thought maybe my urine was too diluted since I took them in the evening so I took one first thing Saturday 10/28 morning and it also came up negative. Today which is Monday 10/30 I went ahead and went in for another blood test this morning and will be getting a call tomorrow. I told them when I got there I didn't think it would do any good, but they insisted that I go ahead. Is it possible that my hcg just fluctuated enough to where it won't show on a urine test or something? I only bled for 2 days bright red and brown and it was much less than a period and only spotted brown for 2 days and then it went away. I never had any pain and never any blood clots. I'm so confused and sad and mad right now. One minute I'm convinced we lost it and the next minute I'm hoping there's still hope but I don't want to get my hopes up again!