Lots of symptoms - need advice please

[yoyooz]

Hi! Sorry this is a long one!
I'm after some advice please! I'm lucky enough to have a 13 month old daughter and 2 months ago dh and I decided to try for number 2!
We've been tracking cycles for around 4 months and last month we did the deed bang on 'peak' time according to the clear blue ov test machine!
Felt fine, the usual no issues other than the dreaded 2ww! Had a bleed about 2 days before I was due on so thought that's me out this month as lasted a good 3 days! Not majorly concerned as we've only really started trying!
For the last 10 days though I've felt pretty rough! Exhausted (and I know exhausted with a baby who still doesn't sleep), horrendous lower back ache (not the slipped disc kind either), cranky, bloated (could be down to the copious amounts of chocolate I've eaten) gassy, and then more recently - like the last 3 to 4 days I've felt nausea, dizzy and had really bad pains down there. Groin region, plus a killer headache today! So as an avid poas person, I did a branded test which said bfn! Again I though that's fine, our bodies can play tricks on us, surely the symptoms will just go now or it could be something else? I'm prone to utis so checked for infection (more poas lol) and all good?! I've done a fair few hpt' s over the last week and all negative! So how do i get these symptoms to bugger off? I'm not due to ov until next week (4 months worth of tracking and a neg poas ov this morning!) So any ideas what the hell could be going on? I'm more concerned that perhaps something sinister could be going on with the sharp pains but no more bleeding?
Tia! X