I think I might be in early labor... kind of long sorry?

I'm 41 weeks & due to be induced on Monday. I did take a little bit of caster oil yesterday lunchtime, don't say anything i was desperate & i chucked most of it up anyway. since about midnight i've been having irregular contractions about 40-50 seconds long every 3-8 minutes. is this early labor or could it be from the caster oil? x