My DD1 had these around a similar age although I think their more common in toddlers. DD1s started when I was trying to get her in a routine and restricting her naps so down to overtiredness. I was on the phone sobbing to my DSIL one afternoon when she'd just woken up screaming again and she told me to let her sleep more and stop worrying about a routine. I did (think she ended up sleeping over 3 hours that afternoon) and she never had another night terror.
My DD would wake every 45 minutes screaming and just seemed oblivious to me being there. My DSIL had exactly the same problem with her DD when she was trying to cut out her daytime nap which is why she advised letting her sleep.
Dd has never been a good napper but she does have a routine of naps however..if she takes them or not is a different matter! Every nap time i have to do CC with her which can take about 45 mins sometimes. When she does nap its never for very long unless shes in her pushchair or on rare occasions she may sleep in her bed for about an hour or so.
Now youve mentioned this i have noticed that when she does rarely sleep more in the day she sleeps better at night...
Sounds very familiar to my DD1. She was never a good napper and often quite unsettled in the evening... Would wake every 40 minutes or so. She did get a lot better though, especially when dropping to one nap a day.
FWIW DD2 has been a dream sleeper in comparison... Pretty much jumps into the cot!