HELP!! Sleeping trouble related to eating!??!

[xXHopeXx]

It's been ages since I've been on here! Life with a baby certainly catches up with you! :/ how I missed BB!!

So.... DD used to be such a good sleeper! Since she's recovered from being sick (TBH, we aren't sure whether she had a tummy bug, teething, or what! But she had a NASTY cough, and dirrhea and vomiting for 2 weeks, and was right on the verge of being hospitalized!) but then, suddenly overnight, when we noticed a tooth, the symptoms nearly completely went away! Coincedence?), since then, she HATES going to sleep most times! Sometimes she's her usual self and goes to sleep easily, but other/most times shes been putting up a scream fest just to go to sleep! Like last night, she went to sleep initially pretty easily, but come around 1am, she wakes up screaming and crying, and was going between crying, being awake and falling asleep for over TWO HOURS!!! Finally she fell asleep on my chest, and then slept til 7am, so around 3.5-4hrs. She's been doing it for some day sleeps too, so it's not just restricted to night time this problem. But other sleeps, she's fine! We put her to sleep as soon as we see tired signs (but occasionally we miss the first ones because were out and she won't sleep when were out)
We don't know if it's behavioral or if she's in pain? Her cries come in waves, as though the pain goes away and comes back like a tummy ache or tooth ache, but distracting her with something like a phone works, (however just picking her back up or changing positions or giving cuddles don't help at all, she just keeps screaming)
Her sleep hasn't been as good as it used to be when she was really little (I.e. She used to sleep 6-7hr stretches, but since like 3-4mos. Only been sleeping about 3-4 hr stretches, 5 if really lucky) but all she'd want is a feed and shed go straight back to sleep! None of this crying and screaming stuff!!
I can't help but wonder if perhaps it's because we've been doing solids? (both a mix of BLS and purees) and it's giving her a tummy ache?? Or could it be my milk? But then I think it hasnt affected her this badly before and I haven't changed anything??

Ahhh bloody he'll I'm too tired to deal with this properly :/

Please help!!!

Oh, we also cosleep, so I use that to get more sleep already