Worried about our dog.

Hi, my question is about my mom's 13 1/2 year old dog, Mandi. She is a mixed breed with Shar Pei and not sure what else she is mixed with. We all have a total of 3 dogs, and Mandi is the largest of the 3, weighing in around 30 lbs. She is at the norm for her weight and the other two dogs are fine. Anyway my question I have is, Mandi threw up two days. She only did it 2 times during the day. This is not like her at all, but we figured she found something that didn't agree with her stomach. The next day, yesterday, she threw up 1x and dry heaved numerous times throughout the day. Today, being day 3, she has been dry heaving a lot! At least 1x an hour. She seems fine besides that. No change in her appetite, no change in her mood, and she goes outside with no problems just as she always has done. One thing I've noticed about her, as the dry heaving starts up, she gets all tense and almost looks like she is is rock hard. Her limbs stretch out and get stiff as she makes these horrible gagging noises (the dry heaving). She opens her mouth yet nothing comes out. I also wanted to note, since this all began, she has not thrown up immediately after her dinner. The vomiting and dry heaving starts up at random times of the day. I am guessing it is acid reflux after reading others posts. We may end up taking her to the vet but we haven't yet since she shows no signs of pain. We want to try home remedies first. Was wondering if anyone had any recommendations?
Thank you,
Tay