Blood pressure at 23 1/2 weeks

I am 23 weeks + 2 days, last night i woke up with the worst migraine ive ever had in my life, and i get them frequently so that says a lot. I was crying, checked my BP and it was at 146/97. Immediately woke hubby up and said i needed to go to the ER, but we decided to drink some water, take Tylenol and calm down, then check it again. When checked again about 15 min later, it had come down to about 123/70. First of all, does that sound like a normal timeframe for it to drop so drastically? Second of all, no telling how long my blood pressure was that high for, should i have gone to the er? My head still hurts and i am worried about if the baby is ok. Advice? Going to the doctor tomorrow.