Recently my blood pressure has dropped in the evenings. Last night it was 144/59 and my pulse was 74. Is this something serious?

That's not normal BP. 144/59 is still considered hypertension -- normal blood pressure is closer to 110 or 120 over 70-80. Normal pulse is from around 55-90 or so. The blood pressure you got is mildly elevated and not considered low. If it is running higher earlier in the day, you may need to see your doctor.
No. As long as you do not have any symptoms this is normal. If you are on medication, this is a normal response. Blood pressure usually rises over night.