I'm no vet, but my first thought was pyrometra, an infection of the uterus. The severity can vary, but needs treatment quickly, since it can be fatal if the uterus ruptures. Even if your boyfriend can't take her to vet right now, I would suggest he call some local vets and see if anyone is willing to do a phone consult or video chat to look at her and advise how urgently she needs care or whether there are any over-the-counter options.
Do you have a thermometer to check and see if she is running a fever? (If she's a feisty girl, it might be a two-person job!)
Where are you located? Maybe someone here can recommend a low-cost clinic or other assistance program in your area.
#PetHealthandNutrition