I think my baby might be sick?

she's 8months old an is usually a really good eater and sleeper, she' slept through the night from about 3months old. but for the last week she's been of her food (milk as well) and she goes to sleep and the wakes up like an hour later screaming, she only had about 7 hour last night an that was broken. also she's got really clingy and cry's till i pick her and won't have a nap in the day, she starts to fall asleep then starts to cry. shes teething again so it could be that, but she's never been close to this bad when shes teethed before. on top of this for about two days now she's had red puffy eyes a runny nose and keeps sneezing and holding her ears like they are bothering her. it's been really hot here just recently so i guess it could be that making her worse or hay-fever. i'm Absolutely knackered so she must be close to fatigue. i don't know if she needs the doctor because shes not dehydrated or being sick and shes not getting worse but shes not getting better either, like i said she had a really good sleep routine an a good eater and was always content to play on the matt. does any know what might of caused this and how i can help her. any advise would be much appreciated. thank you!