Feeling down feeling useless

My son is really poorly he has a chest infection he coughs that much it disrupts his sleep so I don't get full nights sleep he on 3 different meds plus 2 inhalyers I'm so tired plus I'm 8 weeks 5 days pregnant I have my mother slagging me n my fella off for having are 3rd baby telling me it won't b lucked after n my other two will b pushed out then I have my fella telling me I'm snapping at him well I'm sorry I've got so much on my plate to deal with I feel useless n like a mug so sorry for the rant