I've had that vibrating sensation as well - and I'm pretty sure it's where her head is, which she likes to stick under my left ribs from time to time. I get tenderness there quite often so I'm assuming its her head - kicks are...
I'm doing a Cal/Mag/D supplement in the morning along with a probiotic, a prenatal at lunch and Floradix iron + prune juice before bed. Also drinking RRL most days but I need to start upping it now that third trimester is here.
I chose not to do one - my midwife gave me the low down at our last appointment (pros and cons) and basically left it up to me, but she didn't seem like she was a fan of the test for people at low risk.
I'll be 28 weeks on Saturday. I've been really tired off and on for a week now. Also weird appetite again where sometimes nothing appeals to me. The past two days were really rough but I'm feeling better today.
It's a bit long-winded but this is an interesting video on the importance of iron and oxygen at birth, and around the 9 minute mark he starts talking about the umbilical cords role and optimal time for clamping.
Maybe try a support belt when walking or doing anything physical/on your feet alot. I've found it's helping me a bit with the ligament pain and SPD pain.
I have one more week to go until third trimester I think - 27...