Happy birthday! I'd say write it off Rachel. We all have bad days, weeks even. But what we're doing is for life, so it's a given that things will not go according to plan all the time.
Revisit your books and start afresh. Make your favourite syn free or low syn meal. Have your syns. I was really homesick when I first moved out, but I found the more I had my 'creature comforts' around me, the less homesick I felt! After a while, I couldn't remember why I was so down in the first place, I speak to my family almost everyday and I still go down to my 'rents for Sunday lunch.
Most importantly, don't give up. Remember why you're doing this. I've been there and probably will be again, but this is what helps me...that and the advice of all on this wonderful board! Good luck.