Is it safe to take plan b 6 weeks after birth?

So I just got cleared to have sex again by my dr so we have sex for the first time in 2 months yesterday. My husband pulled out the first round and the second round “forgot to.” 🙄 So my question is, is it safe to take plan b this early after birth when I haven’t had my first cycle? I called my doctors office and they haven’t called back yet.

P.s. I’m allergic to birth control and will be using condoms from here on out lol