My kitty has started peeing again

backstory:

I just moved in with my BF and he has a dog so we keep the cat in a back bedroom, but let her out while we're at work (dog is in the dog run) from 9am-6pm and then she is out at night and the dog is crated in our bedroom 12am-6am. She also hangs out with me while I study in the office from 9pm-12am so we try to make sure she gets her own cuddle time and the dog goes on playdates every few weekends so the cat has the run of the house. We're slowing introducing them...but the dog isn't too keen on it, yet.

She has peed twice in the past 3 weeks, once on some blankets in the closet, and then again in the closet (2nd time there may have been leftover smell). Both times I cleaned with petsmart cat cleaner (this is my fave- I've used nature's miracle and a few others before). I also have a feliway plugged in. I put foil over the peed on areas and I could put an upside down carpet runner in the closet...but her box is in one corner of the closet.

I'm going tonight to pick up more cleaner and litter attractant (ran out so her box was not treated). I think she may be stressed from the dog, but she seems fine and she's bold around the dog, ie runs out of the bedroom in front of the dog, stands up to the dog, etc etc. She is not a timid or scared cat by nature, but maybe she doesn't have physical signs of being stressed except the peeing. Anything I can do for stress? I'm 95% sure it is not a UTI because there are no UTI signs and she's had one before and I know what to look for.

Any help is appreciated and sorry for the longwinded post!!

I just really can't afford to do it all the time because my cat likes to pee on bathmats and littler mats (no litter mats anymore and I close bathroom doors) and getting her checked out once a month or more at $200+ a pop is just out of the question. If it keeps going I totally will...but being that they are isolated incidents I have a gut feeling that it's not a UTI. I got a black light and cleaned any spots I saw in the room so hopefully that helps.

the one UTI she had was 3 years ago and she's been checked about 6 times since then and been cleared each time. My vet thinks she has anxiety from other animals. Her box is in the closet. I think I'm going to try taking off the lid for a little bit, but in the past she hasn't shown improvement with the lid on vs. off. I use pet enzyme, it's petsmart brand. In the past I've used natures miracle, simple solution and the baking soda/detergent/peroxide mix and I like this the best so far. I also use a black light to look for spots. I scoop once a night and change the littler usually every 2-3 weeks depending on how bad it is.

I've cleaned out the whole closet and I moved all of the littler and cat cleaning items away from the closet (incase they had some kind of scent) so we'll see.

the closet doesn't have doors. and she's just confined to one 10x10 room so I thought 2 boxes would be overkill...but I have a mini one I could put out. I posted here and on a dog forum about intros and we're trying but it's not really progressing very well. I have a friend of a friend who is a dog trainer so we might get her help with the dog. If the cat keeps up with the peeing I might go to the vet and see about her anxiety problems.

Thanks for all the suggestions!

by checked out I mean she had a urinealysis (sp) done which came out clear and the test done where they try to grow bacteria and nothing was found. Her boxes are never bad, I just meant when the litter starts to get darker in color and 2-3 weeks for one cat is reasonable imo...with my other cat we went a month or two. I do add clean litter to keep it at about 3 inches and the litter never smells unless she just pooed.

well, the room is about 10X10 so the feliway can't be too far away but it's on the opposit side of a bookcase about 4 feet away. I can move it too an outlet about 2 feet further...that would help.