HOW CAN I GET BETTER??

I have been an emotional basket case for several months now due to my sons father leaving...and not having my son full time. i get depressed easily and suffer with severe anxiety. on top of this i live in pa where is snowing cold and rainy all of the time, and i work in a school. i have a different ailment or virus every week for 2 months now it seems, colds, stomach flu, constant Diarrhea, sore throats, fever and now a nasty cough. is this due to stress? can if affect your immune system and if so what can I do to get better? i have a 3 yr old work and go to school and i cant take anymore. help.