Mucus Plug? 21+4 and worried

Cara

So I went to the bathroom and felt something "stringy" and pulled and this was it. Could it be part of my mucus plug and is that normal? I just had an ultrasound 4 days ago and everything was good. I've had no cramping or blood or anything like that.

It feels very thick and springs back if I pinch it rather than separating.