I wouldn't say call for help straight away, if you find yourself lost, pick an area below that you can recognise and orbit it, like a football pitch... then use the methods to get Un-Lost!
Bad call my friend.
If you are lost, you do not know whether you are in or outside controlled airspace, overflying a restricted or danger area etc.
Under these circumstances, an immediate call to D&D on 121.5 is needed, to do anything else is poor airmanship as you may be interfering with other air traffic.
The only time I ever started to feel unsure of position was on a hazy day ,with no clear landmarks and I called 121.5 for a training fix.
This told me, within 10 seconds, where I was (still over a mile outside CAS) and allowed me to re-establish certain navigation.
Of course that was in the days before GPS, or I would never have got close to CAS.
So if lost, please do not b*gger around, get help.
The D&D want you to do this and so does all the traffic in your locality.
At 7 hours TT, your instructor is unlikely to have shown you the procedures yet, but when s/he does, listen carefully as it could save lives.