Anxiety eating away at me

After the joy of the strong positive on Saturday I just can't relax now.  On Monday I confidently phoned the clinic to ask for my paper work to be sent through so that I could go to the GP to get some more progesterone pessaries.  Since then my confidence has waned.  I can't think straight and I can't think of anything else other than losing this baby.  I know technically he's a ball of cells still but it should be a well-formed blob now, starting to resemble a tadpole-esque baby.

I haven't had many concrete symptoms.  All I have to report is that my boobs are now a bit tender (I keep prodding them to check) and I have a few blue veins on them.  I am also really hungry all the time but this could just be greed or the last few weeks of illness catching up with me.  My OHSS tummy has gone down to what it was almost prior to egg collection and so I'm now worried that my hCG isn't high enough as surely it would've continued to grow/stayed the same.  I am also weeing often but I think this is more to do with getting rid of the fluid that's been hanging around my abdomen for the last couple of weeks. So all of these 'symptoms' can be explained.

Yesterday I got my hospital letter which states my "LMP" (not a real date) is the 17th June and that my EDD is the 22nd March.  The internet calculators I have used worked it out as being the 19th March.  So all in all I'm about five to five and a half weeks pregnant. It's not much is it? Every day is going so so slowly it's unreal.  I have to phone the clinic on the 1st August and they will arrange my scan for some time in the week commencing 8th August so it's still weeks away until we will see our baby again, hoping he's changed from the little white blob on the screen to a bigger blob with a beating heart. My biggest fear: That he's not there.  There is no baby.  He's stopped growing.  There's no heartbeat.  I am constantly looking up things online to try and make myself feel better but often I just feel worse.  So many people miscarry.  Most people can carry on and try again the next month.  Not us.  I just want to hold onto our embryo forever, til he's born screaming.  No one can guarantee that.  I know that I am lucky - we have got this far.  We are one of the 40% who get a positive test.  Let's just hope we're the 1 in 3 who take home a baby at the end.