How often do you have sex?

My boyfriend and I have been together for almost a year & most recently we moved in together. Looking at the calendar on my app, I noticed we have only had sex 1 time this month, twice last month & about 3 times the month before that. When we first became intimate we would have sex 4-5 times a month so once a week basically which was good for both of us. But it has just died down. I will say between July & early this month I was sick so I know that played a major role. Plus we both started new jobs that have us working long hours at the beginning of August. Now things seem to be settling down but we're both so damn tired it seems. Is this normal? I mean we're not even married yet & I just don't want us to get in a rut.