How’s your week off going? I’ve just found this link to The Merriam-Webster’s Dictionary, where you can practise all those sounds you have problems with; it’s American English.
The BBC offers you some links to practise “similar sounds”; follow this link and click on the blue box on the right. Here you will be able to practise sounds individually, just click on the sound you want to practise and watch the video!
Have they been of any help to you?