My cat has been straining to use the bathroom and I haven't been told how to fix it yet by vets and it's getting worse.

I'm an adult USA vet accessible cat age between 1-2 years female spayed depending on the vet care I can or can't afford it

Opal my cat has been straining to go poop I've gotten a few medicines at various times or an it's normal for some straining (I think once) but she has started bleeding after using the bathroom. It's not for long and one of the people I'm living with is wondering if it's a fiber problem she gets 1/2 cup iams proactive health healthy adult salmon and one 3oz can fancy feast gravy daily she is at a healthy weight. When she was bleeding today (it was a few drops but I still worried) they told me to go to a different vet because they didn't have any open slots I didn't tell them how much she was bleeding because I was panicking, I asked what she might need as a treatment and they mentioned a check up ultrasound or X-ray I am sure I can't afford an X-ray and I haven't yet asked about pricing for an ultrasound but Opal needs help and I want to help her. I'm hoping someone here may have an idea of where I'm going wrong. I know I can just research but I don't want her to go through more pain because I have to figure out honest sources/trial and error/whatever else may come with the territory. Any help is appreciated