Beta hcg rising but not doubling

Was about 2 days late for my period on Sunday night so I took a test and it was positive. We have been trying for 2.5 years with no success. Was very happy. Had my beta hcg drawn on Tuesday of this week and the number was 210. Had it done today and number was 337. So it didn’t double in 48 hours. The OB nurse I spoke to on the phone said not normal but could possibly be ok. Two other drs that I work with have told me conflicting things. One says definitely not normal probably ectopic or blighted ovum. The other dr says normal. So wtf! Please someone help me out here. I’m going insane.