Painful Left Lower Abdomen: Scared

Hi, ladies! Okay, I'm turning to all of you because I'm starting to panic and panic hard; I'm several days shy of 21 weeks, and over the last week or so, I've had an constant aching pain (feels different than ligament pain) on the very outside edge of my left low abdomen; it's painful if I apply pressure to it, and it is "uncomfortable" all of the time (when I sit, stand, bump it, etc...). I'm terrified of placental abruption. I talked to my midwife yesterday, and do have any ultrasound on Monday 🤞I've had no bleeding, back pain, contractions, etc, just the constant discomfort; it feels like what I would imagine a hernia would feel like (however, no hernia bulge). If I massage it and/or stretch the pain dissipates, but only for a very short time. Anyone else experience this?