Hi ahmedkl, welcome back! I understand what you are saying, F2L can be a little bit confusing at first and it is common to see an initial increase in times as you get used to the idea.
To be honest, at this time, I really think it's best if you don't time yourself. Solve the cross and then find your first F2L pair. Probably a good way to start off with this is just to take the first corner or edge that you see, and then look for its partner piece, even if it isn't on the top layer at the moment.
Once you've found a pair you want to solve, just take a moment to think about how you want to bring them together. Don't be afraid to undo what you've just done and see if you can find a better way to partner your F2L pairs. To be completely honest, when you're getting really fast with this method, you tend just to be able to glance at a F2L pair, recognise the case and know how to piece them together immediately. You even start coming up with your own "algorithms" to set up or bring together the pieces.
A bit further down the line, you will become able to see a case which will be so familiar to you that you can solve it without looking. Advanced CFOP users use this time to look for the pairs they are going to solve next, we call this "looking ahead".
For now, really just take your time. Don't worry about being fast, instead, try and be efficient in your corner-edge pairing and just become more familiar with the whole F2L process. Don't just do solve after solve after solve, really take your time and concentrate on F2L.
Good luck, and remember: Go slowly, take time to think about different ways you could bring the pieces together before you solve them, and don't be afraid to undo what you've just done and try something different.
