I'm four weeks late and I've been getting neg. Tests should I get blood work I've never been late even when I had cervical cancer im four weeks late I've taken a lot of tests and I got a couple back with faint lines should I just get blood work done.

Ask your provider. Over the counter pregnancy tests are pretty darned accurate so you're probably not pregnant but if you're four weeks late you should talk with your provider because there are other reasons your menses could be delayed.
Yes, . Yes, if you still have not gotten your period then please have a blood pregnancy test taken. It is more accurate than urine testing.