Texas has really strange weather

At the end of this month, we will have been in the United States for four months. Since we have been in Texas we have experienced almost every season. When we arrived, it was warm enough to wear sandals and shorts. A few days later, it cooled down, and we wore warmer clothes. At thanksgiving, it wasn't too warm or too cold. It was probably in the 50's and the 60's for most of December, with some rain. January we have had freezing rain, and ice. It was so cold that we had the heater all the way up to 75. February hasn't really been all that warm, but for the first half of it I was in California, where it is usally mild weather. When I flew in, I was wearing flip flops, and it was 40-something degrees outside. But yesterday, it was in the 80's and we went to the park, and my arms actually got some color on them. My point to all this rambling, is that because of these extremes in the weather me and my poor kids have been sick on and off for the last four months. At first it was just colds. At christmas both of them ending up with ear infections and we spent time at the ER and urgent care during our short visit to California. Andrew has been to the ER since we've been in Texas, and Lucy has had a few fevers since we've been here, but nothing too high or scary. We are just not used to being in the US. Our poor immune systems are suffering, and the screwy weather isn't helping us!! At the moment, I am still recovering from something that I picked up while in CA, Andrew is coughing so much he wakes up at night, and when Lucy coughs, it just sounds like she is so congested! You might say, why don't you go to the doctor? The doctor can't do anything for a cold, and whenever I've taken them before, they just tell you a bunch of crap like "it can take up to two weeks for the symptoms to go away." Great. So they will be coughing for two weeks, and they don't give me any medicine that I can't just buy over the counter. So, a total waste of time. I guess I'm just tired of kids being sick, and now that I'm sick too, I've had it. If only they would find a cure for the cold......
It doesn't help that over the counter decongestants for kids NEVER work. Neither do cough suppressants. Total waste of money..... I do do the herbal stuff. I put peppermint oil and oil of oregano in a vaporizer and that REALLY helped Andrew's cough last night. And I should be giving them both the elderberry syrup a little more consistently.
If any of you out there have suggestions that have worked for you or your kids, let me know. I'm hoping that once we are over this round of colds that we can stay clear of sickness for the remainder of our time here. Its only 10 more months....thats not asking too much is it???