Some Relief, Some Concern

So I had my second ultrasound today, and, after much nervous silence and prodding of my belly, the doctor at last found within the the black, cavern-like expanse of my uterus a tiny little blip of a baby with an even tinier little pulsing blip of a heartbeat. Yay! It took probably half a minute before he could maneuver my uterus into a position where the heartbeat was visible, during which time I was thinking, with a sense of dull dread, "Oh, are you kidding me? Not again." When he finally pointed it out, I let out a loud little exhale of relief, breath I didn't even know I had been holding. And then just as quickly I demanded, "What is that, another baby?" For lo and behold, there was a smaller black blob of something or other floating around near the gestational sac.
But no, don't go congratulating me on twins just yet, for it really was a lot smaller, and the doctor was actually a little concerned about it as he thought it might be fluid leaking from the sac or something. But, I had also had a large cyst on my ovary just last week which was no longer there today, so my humble little layperson guess is that the random black blob is just leftover fluid from where the cyst burst, something which happened to me before, since I am what one calls "prone to ovulation cysts."
But again, one more thing to worry about, darn it all. The doctor said I should start taking progesterone supplements (and those are in vaginal suppository form, lucky me!) just in case the sac is weak and needs some extra support or something. I don't know. Tell you the truth, I am growing somewhat skeptical of what doctors really do know about the miraculous process of conception and birth. I think half the time they're just scratching their heads going, "Well, hmm, here, try this, can't hurt!"
My husband calls it the curse of science, how we on the one hand have such amazingly early diagnosis of pregnancy and 4-D ultrasound and all that, but we are also able to find all these slightly variant things which may or may not be a problem, but because we can see them and test for them, we are psychologically unable not to worry about them. Well, I am unable, anyways.
It's still a relief, though, to see that little grain-of-rice baby there. Even though it only measured at 5 weeks, 5 days, quite a bit off from my supposed point in pregnancy, 6 weeks and 4 days or something, it is a baby nonetheless. So they changed my due date to September 9th, which I just sort of shrugged at. Due to the Clomid and the weird testing flukes I encountered when I thought my period was due, I have honestly no idea whatsoever when I conceived, so it's entirely possible I am not even six weeks yet. Fine by me! More time to prepare myself for having two little ones around.
I just want that to happen. I just so much want everything to be fine. Come on, gestational sac, get to work!