I've been there!
I try to minimize medical intervention in pregnancy and am careful about what I put in body, but that said......I wouldn't say no to terbeutaline if my doc recommended it which they did with both pregnancies. Pre term labor is scary to fool around with. With my first one, I had to take it in pill form around the clock. I wasn't sure it was necessary, but was afraid to skip it and go into labor..... With the second one, I only had a shot of terbeutaline once. After that, I really watched my fluid intake and rested when needed. I continued to have mild contractions throughout, but did not need the terbutaline to stop things.
The ironic thing is that with both pregnancies, I tried so hard to not go into labor early and had to be induced both times for toxemia!
Sending calm thoughts to you