Separation Anxiety?

I think Summer has some very mild separation problems. She's fine at home, where there are other dogs when she's left alone but here she's not.

She's good when I leave. I lock her in my room, which is puppy proof with some toys/chews, her kennel open, food and water, and the tv on. I'm only gone a couple hours at a time. Monday, though I changed my schedule and will be gone from 8:40 to nearly 3:00. That's the only time she's alone very long at all and my roomie can let her out about noon anyways, so she's really only alone from 8:40-12:00. When I get home, and open the door, however, she goes nuts. Doesn't matter if I've been gone 5 minutes or 5 hours, the reaction is the same. She cries and barks and yaps from my bedroom until I open the door to let her out. When I let her out, she zooms around the house and jumps all over everything, jumps all over me for about 5 minutes and then she calms down fine. I have been trying to get a treat and make her sit and behave right after I let her out but I don't know if I'm handling this well.

Anyone have any advice on how to get her to calm down when I return home? And also how to be calm if she's locked in her crate/room while other people are home?

Well, first of all, it's not a great idea to "get a treat and make her sit," your treat is a bribe and she's learning very little.

I'd suggest not ever letting her out of the bedroom unless she's quiet. Letting her out when she's all worked up, barking and yapping, etc., is only rewarding that response to you coming home. Make sure that your roommate understands not to let her out until she's quiet, as well. Sometimes it takes quite a while for her to quiet down, especially in the beginning after a reinforcement history has been established, but it will happen eventually.

Once you let her out, even if she's being quiet when you open the door, she'll probably be very excited to see you. Try not to give her any attention at all until she calms down - don't look at her, talk to her, take her outside, etc., until she calms down again.