Vent about fighting....

It's been a while...after the holidays I started a new job so getting online hasn't been common! But I had to pop on tonight...last night Abby and Brady started fighting. They only ever fight over a new toy and rawhides. The only time it has been for another reason is when they had some jealousy issues after we returned from a week long vacation.  
Now, last night, a new toy was involved, but I monitored them and as soon as I saw some possessiveness, I put the toy away. Despite that, they started to fight. I separated them and after a few minutes of cooling off, I carefully re-introduced them. They went at it again. This has NEVER happened...they typically are all lovey with each other immediately. So I separated them again, took each outside individually, gave them some time. Then, they went at it AGAIN! So I kept them separate till my husband got home from a dinner meeting and we worked together to re-introduce them. THey were cuddled up with each other within 15 minutes.

Tonight, Abby seemed a bit possessive of an old ball, so I took it away. She saw where I put it in the other room and went looking for it...she returned and attacked Brady! WHAT THE **** is going on?!??!?!  (of course, although it is the last thing you are supposed to do, I always push them away from each other and pick Abby right up so they can't reach each other...tonight, I stuck my hand right in her mouth...ouch!!!!) I felt awful for Brady...he was so nerved up, he woke up at 4 a.m. puking.

Anyways, not sure what to think right now.  Moments before tonight's event, they were playing. She's 18 months now...is she in a new development stage? The only thing that has changed, and maybe they are feeling it...it my new job. I am working longer hours, so my husband comes home a bit earlier (the time I used to) to take are of them. Their hours are technically the same...it's just my husband getting home to them first, instead of me.

I don't get it. Brade is curled up in my lap right now, poor boy.

Sorry for the long vent, but if anyone has any thoughts, suggestions, etc., let me know.

(I should note, Abby clearly knows she is in trouble...once she calms she just looks at us  like "uh oh." We give her a time out and make her sit/stay...she would stay in that precise position hunched over for an hour if we didn't let her get up...she knows she's in the wrong.)