Should take her to the ER vet??

Abby has not been able to poop today and she only peed a little. I didn't clean her box yesterday but when I cleaned it today it looks like she has pooped, but small amounts (several of them but small). I have found three little pea sized "balls" of soft poop with mucous in them and she has a little mucous on her butt now (very very small amount). She did eat dry food today and a little of her wet. I broke down and gave her a small amount of just Friskies and I noticed that she did eat a little of her mixed wet.
I fed her about a tablespoon of pumpkin this morning.
I little background. My husband I just moved 1000 miles three weeks ago. Abby has had some behavioral issues with the move (to be expected) but she's been eating fine. I have been unable to find her the Max Cat Light so she's been eating friskies wet (junk I know but she loves it) and her Purina One dry. I am now slowly switching her to California Natural wet and Nutro Weight Manegement dry.
Could it just be a case of too much change all at once or something more serious?
I am new to the area so I don't have a vet yet but I checked the phonebook and there are a few ER vets that are open now.
I hope I am just being an over worried Mommy but being new to the area I don't have the comfort of my regular vet.

Thanks for reading all this.

If it's an emergency I would take her, but it doesn't sound like it's an emergency to me. I would definitely think about taking her tomorrow since this doesn't sound like something she normally does. Doesn't sound like she's blocked since she is going, but a vet would better be able to tell you what's up. Unless it's getting a lot worse really fast, I wouldn't take her to the ER just yet. But that's my opinion. You know your cat better than I do. Good luck! Sending good vibes your way.

It could very possibly be the switch in food. Some cats can handle switches well, others have trouble. Switches should always be made gradually over a week or two.

I would say it warrents calling the ER vet and getting there opinion... If you are lucky like I am your ER vet will NOT want a non emergecny in there ER clinic and will give you advise on what to look for or do till tomarrow