Do I call him or let it be?

I have a boyfriend and past month we had too many fights and on and off, we have been together for 8 months now
Untill Saturday everything was ok and i saw him and we agreed that he will ask for Thursday to be his off so we can spend the day together.
I texted him that day the normal and he didn't respond to me
I called him then at 10 pm and his phone was busy and he never got back to me
The next day i called him, he didn't answer i checked on him by noon and his phone was also busy
When he got back to me on Sunday i asked him what is wrong and why you didn't answer me, he said he was tired and sleeping , and that he got to work and will call me back. And he never did till today, i feel sth wrong and i don't want to seem like the clingy one
Do i call him see if we are still on for Thursday, or just leave it and ignore him
Ideas please
Do I call him or let it be?
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