Back ache.. please read! (Posting in a couple groups)

Hello ladies!

Firstly I'm currently 11w+6d with twins. Today I have been stupidly busy, I've been on my feet most of the day & pushing my 2 year old around in his pram, allllll day. I was on the go pretty much power walking and pushing the pram from 1 till about 4 continuously and I've just in general had a busy day and been mostly on my feet. I don't usually do this much, so I'm not used to it. I now have a really really dull back ache and I've had it for about an hour or two, I could've had it longer but think I've only noticed it since relaxing this evening, it's not painful at all but it's just constant and very dull. I have absolutely no cramping and no odd discharge or bleeding. I also have a cyst on my left ovary (found at a 10 week scan which they said caused the bleeding & there was still a small bleed by it but they weren't worried at all) and I've had a really tight feeling & almost pinching like sensation where that is, I've had this before but it subsided and now its back. I've got nothing else going on apart from I haven't ate much today, I've ate enough but not as much as I usually do but I'm very hydrated as I've not stopped drinking iced water all day! Since finding out I am having twins I've been noticing every single last twinge, or feeling. It's been crazy and i have my 12 week scan on Monday which I'm very nervous & anxious about. I know I'm probably just being silly but just wondering if you ladies agree that the dull ache is probably just from the busy day that I've had today and I just need to rest? ☺️✨