Agonising cramps! Help!

11+5 (so close to that magic 12 week mark!) I've been feeling a bit crappy all day, From when I got out of bed I felt hot and had no energy.

This afternoon I've started having agonising cramps- just like period pains. It's worse when I'm stood up or moving around. No spotting or bleeding but I have been suffering from constipation and trapped wind over the last few weeks.

In my area you can't get seen at a weekend so have to wait til Monday but in the meantime can anyone give me any reassurance? Does it sound like uterus stretching/gas/constipation or something more serious :/