I Feel Very Weak And Like A Bit Shaky Inside

I feel very weak and like a bit shaky inside all the time. I don't know if dizzy is correct because I don't feel like the room is spinning, but I feel like I am always going to pass out. I have had blood work and there is not anything significant. I check my blood pressure and pulse when I feel really bad. I usually have lower blood pressure which at times has been very low 70/40 when I feel really bad, but my pulse is usually over 100 when it happens also. Any suggestions?