I took 2 mental pills and 3 sleep aids, by accident, should i go to the er?

Yes: To be safe, gather all your pills and go to ER for evaluation & monitoring. Review your medications w/prescribing doctor(s). Make sure every doctor knows what you're taking, whether prescription or over-the-counter, even dietary supplements. Set up pill planner or alarm on smartphone to minimize risk of this happening again. If suicide gesture, seek counseling.

Depends: Depends on what medicine you took , the dosage in each pill, and whether there is interaction or not, I would at least recommend you call a local emergency mental health number immediately and discuss the issue with them and follow their recommendations get well