big lump on underbelly, also possibly pregnant

i had some tenants abandoned a kitten about a month ago. Orange tabby, she is adorable. I dont know her exact age, i believe around 4 or 5 months . She has a big lump on her underbelly . i was told possibly a hernia. And now i think she might be pregnant. I cant afford an expensive vet bill. But i do know she needs to be seen asap. Is she in any danger if she is pregnant? and i live in carlsbad new mexico. not a large town by any means.  I want to keep her, ive grown quite attached to her.. she even sleeps next to me every night

Hello - what a heartwarming story of you making room for this stray - so much so that I'm afraid I don't want to answer the question.  A hernia and a pregnancy is only one explanation for an enlarged abdomen with a lump below it.  Cancer or liver disease may look like this too.  Obviously you can see the cat and I can't, and she is the right sort of age for getting pregnant, so I am going to answer assuming that you are correct.

Pregnancy does increase the pressure on the abdomen - and, particularly where there is a freely-moving hernia (I mean one where the abdominal contents can slip in or out of the hole), then putting more pressure - a few kittens, say - in the abdomen, can cause the hernia to grow or even to strangulate.  This would be life-threatening.  The fact that you have identified the cat as pregnant may imply that she is rather near her time; has she mammary development, for instance?  I'm afraid that I would indeed recommend that she goes to the vets - perhaps, if she is about to kitten, she has escaped from somewhere and may have a microchip.   Failing this, a choice has to be made.  Perhaps you will accept ownership of your new friend which makes you responsible for a vets' bill, or perhaps you could ask what would happen to her if you were to hand her in as a stray.   Of course in the ideal world she would kitten without incident, or the lump would turn out to be something else, but I think that you should be prepared.