Just give them some time, they will be okay. When we first brought Jackson home, Jake was a little over a year old. He is very much a mama's boy, so he got mad at ME. He wasn't mad at my hubby, just me. That, of course, broke my heart, but I just made sure I gave them both the same amount of attention, and I would take Jake outside for his "mommy and Jake" time so that he wouldn't be so upset. He stayed mad at me for about 3 days, and he really didn't want much to do with Jackson. He would get curious and check him out, but he wouldn't play with him. Jackson was a 10-week-old puppy, and he wanted to play and run around. Jake would sit on the couch and watch him, but he wouldn't play. I was lucky though, neither one of them nipped or growled at each other.
After about the 4th day, they started playing together a little bit. Then, the two of them had a little barking match. Jake rarely barks, but he started barking at Jackson over a toy. Jackson barked back. This went back and forth for a minute or so, then they both just started playing and have a good ole' time, and they have been best friends ever since. It was like they both got the rules straight lol.
It's hard, but don't get discouraged. Give them a little time, and I bet they will be playing together.
As for her being pregnant, I sure hope not! I can't help you with that, but I do want to wish you all the best.