Implantation Cramps/Bleeding

Hi ladies !

Before i express my concern. First time mommy here. So I’m nervous.

6/22/19 I was confirmed pregnant. Very early as i was only 10 MIU/ML. naturally it’s gone up since. As shown in the photo ! What was interesting is that i had not had my period since April 7th ! Of course they set me at 11 weeks pregnant based off of that but my husband and i didn’t really start trying till the beginning of June. And i new i wasn’t that far along just based off of my levels from my blood pregnancy test. But they insisted I am until my ultrasound. I had my ultrasound done this past Friday (6/28/19) attaching photos. My nurse told me i am definitely under 4 weeks. They did my paps, pelvic exam & then used the probe for the ultrasound & expected a heart beat because they thought i was 11 weeks. Lol but i am definitely under 4 weeks as all you can see is my sac & thickening. When they did my paps, she said everything looked good , everything was “closed up” lol, she also noticed some old blood on my walls , she said she was cleaning it up , nothing to worry , just old blood. So fast forward to now : I am experiencing on and off cramping, mild , kind of like the feeling where your period is going to start but not as intense , and when i wipe there is some brown discharge. I put a liner on , and it’s a medium dark brown, not a lot. But the cramping concerns me. Should i be worried ?