Could there be bedbugs in my bed?

I'm not an avid bed sheet changer but for the past few weeks I've been EXTREMELY itchy on my head, neck, chest, stomach and there's these itchy red bumps on my shoulders (I wear t-shirts to bed) that appear frequently now. Actually it it feels as if theres things crawling on my skin and my head but I originally thought they were just halucinations I admit I should change my sheets but I'm wondering are these bed bug bites?